A Tale of Two Masters
August 23, 2026 Speaker: Martin Slack Series: Romans
Passage: Romans 6:15–23
A Tale of Two Masters
Romans 6:15-23
We’re back in Romans and the passage that was read to us from chapter 6. Before we look at it, I want you to imagine a slave - picture him or her standing there.
What are you seeing? I can almost guarantee what you’re not seeing. You’re not seeing yourself, are you? You’re probably imagining a victim of race-based, 18th Century, transatlantic slavery. And the reason you’re not seeing yourself is that we don't think of ourselves as slaves.
And yet, in today’s passage, Paul says every single one of us is a slave. Why say that?
Well, look at v15: ‘What then? Are we to sin because we are not under law but under grace?’ And Paul is anticipating objections to what he’s been teaching so far: that we’re not saved by observing God’s law and living upright, moral lives. We’re saved by the unmerited, unearned grace of God in the Lord Jesus Christ. As he sums it up in v14, ‘Sin will have no dominion over you, since you are not under law but under grace.’
So Christianity is not, if you want to be saved, and stay saved, you need to keep the rules. No, Paul says, you are saved by grace, and you live by grace.
But that immediately throws up objections, doesn’t it? Then and now. Because if God is merciful and kind to me even when I don’t deserve it, if his forgiveness cleanses every sin - why bother fighting sin? Because if you’ve ever tried it, it’s hard to do! And, let’s face it, sin feels good - and doing this thing I know I shouldn’t makes me happy. And I know it’s technically wrong, but if there’s grace after, why not just do it?
Why not just sleep with my boyfriend or girlfriend? Why not live together before marriage? Why not break the speed-limit when there are no speed cameras around? Why not use AI to make myself look more knowledgable than I am? Why not mock those I disagree with politically? I mean, it makes me happy! And I’m under grace, not law!
To which someone else, a religious, conservative person, might say: ‘exactly. All this emphasis on grace, on the gospel, that just encourages sin - you need to tell people to obey.’
How does Paul answer that? Verse 15 again, ‘Are we to sin because we are not under law but under grace? By no means!’
Why would a Christian even think like that!
But why not think like that? Why shouldn’t we sin if there’s grace to cover it. Well, Paul’s answer is, it all depends on which master you’re serving.
You’re a Slave to Something
Verse 16: ‘Do you not know that if you present yourselves to anyone as obedient slaves, you are slaves of the one whom you obey, either of sin, which leads to death or of obedience, which leads to righteousness?’
So, two masters are vying for your service. And we’re either enslaved to sin, or obedience. We’re either mastered by sin or, v18, we’re ‘slaves of righteousness’; it’s either sin that rules you, or v22, you’re a ‘slave of God.’
Now to be told, ‘you’re a slave to sin’, is offensive, isn’t it? ‘Hey I’m my own master, I’m not controlled by sin. I’m free! No one tells me what to do!’ To which Paul would say, ‘exactly, your personal freedom is your master. You’re a slave to it. It controls your life.’ You won’t be tied down, and so freedom robs you of the very things that give life joy and meaning, like committed love and deep relationships, which always tie us down.
And freedom means keeping your options open, so you won’t long-term commit. But that also controls you, doesn’t it - and you end up paralysed and unable to walk through a door of opportunity, because that would shut other doors. So rather than it giving you the future you want, allow so-called freedom to master you and it leaves you frozen in the present.
And Paul is saying, you’re a slave to that thing that controls you, that you follow and obey - that thing you present yourself to. And if it’s anything other than God, by definition it’s sin.
It could be the approval and validation of others. You want their praise so much it controls you. And if you have kids - you need them to be exemplary - not for your kids’ sake - but because you need people to look at you and go: ‘how do you do it? Your family is so wonderful - tell me your secret.'
Or maybe it’s envy. You look at someone else’s life or social media feed, and you compare - your life to theirs - and it eats away at you. It begins to control you: you need what they’ve got or you can’t be happy.
Maybe it’s some romantic relationship, or career ambition. And before, there were things you said you’d never do, that you’d never compromise on. But then this opportunity, or this person comes along, and you get the chance to be paid that much, or date this person - and your previous beliefs are jettisoned. Why? Because you want this other thing more. Romance, ambition - it controls you. It’s your master.
And Paul is saying, we’re all living for something. We’re all serving something. We’re all laying our lives down on one altar or another. And it’s either God, or something other than God. Whatever it is, there will be some cause, some object, some ambition, some desire, some person, some god who owns you and has you. That masters you. And you give yourself to it because you think it will give you what you want. And it ends up controlling you.
Now, you might hear that and say ‘great, but what has that got to do with law and grace and grace encouraging sin?’
Well, when we picture a slave, we think of an Afro-American slave - for which no-one volunteered. But slavery in the Roman world was different, because to some degree it served as a social safety net. And in the absence of unemployment benefit, or social security payments, if you had no means to put food on the table, or a roof over your head, you’d offer yourself to someone as a slave. And they’d feed you and house you in exchange for your labour, of your life.
And Paul’s point is, when someone does that - when you give yourself to a master - you don’t then turn around and say, ‘I’m going to live like he’s not my master.’ No, who your master is has radical implications for how you live. And God and sin are very different masters.
Different Masters, Different Beginnings
Earlier this week Su and I were talking with one of our daughters about her little daughter - our granddaughter. And she was saying she is getting cheekier by the day. Paul would call it something other than cheeky! Because they will tell her she can’t do something - like lick the bottom of their sandals - and they will watch as she crawls over to those sandals, picks one up, look at them, they’ll go - no! - and she will smile - and lick.
Now did they have to teach her to do that - to sin with a smile? No. In fact, my daughter said, ‘how could anyone not believe in original sin?’ That we’re born sinners. As GK Chesterton wrote, ‘Certain new theologians dispute original sin, which is the only part of Christian theology which can really be proved.’ And if you ask, how can you prove that? you have clearly never tried to tame a toddler, and if you doubt it I would be happy to give you a tour of our Sunday School classes.
Verse 17-18, ‘But thanks be to God, that you who were once slaves of sin have become obedient from the heart to the standard of teaching to which you were committed, and having been set free from sin, have become slaves of righteousness.’
So from birth up, we’re all slaves to sin. Our natural inclination is to put ourselves - and not God - first. To do what we want, not what he wants. To insist the world revolves around us. I mean no one ever has to teach little Johnny to hit his little sister, do they? Serving sin comes naturally.
But slavery to God begins supernaturally. We’re born slaves of sin, but we need to be reborn as slaves of God.
Verse 17 again, ‘you who were once slaves of sin have become obedient from the heart to the standard of teaching to which you were committed.’ So the teaching of all that God has done for us in Christ, the gospel that Paul has been setting out in the chapters before - is the standard, the plumb line by which all other teaching is judged. And this radical change in our lives of going from a slave to sin to a slave of God, begins by becoming obedient to that gospel, by believing it.
But did you notice how Paul puts it? The gospel, this standard of teaching, ‘to which you were committed.’ Not, ‘this gospel which was committed and given to you’, but ‘you were given to it’ - passive tense. Some power from outside you did it.
It’s why Paul begins v17 by saying, ‘Thanks be to God…’ That’s how this change of masters, this change of households happened. That’s how - if you’re a Christian - you were freed from the power of sin and given to God - God did it. As Paul says to the Colossians, ‘He has delivered us from the domain of darkness [we might say, slavery to sin] and transferred us to the kingdom of his beloved Son, in whom we have redemption [the freeing of slaves], the forgiveness of sins.’ (Col 1:13-14).
And now that gospel, that standard of teaching, all that Christ has done for you, masters you, Paul is saying. And not just your head, but your heart: v17: ‘you who were once slaves of sin have become obedient from the heart to the standard of teaching.’ So this is not just intellectual, or moral, or ethical assent to the principles of Christianity. This change of masters - from sin to God - involves change at the level of your heart - of what you most want and what you most love.
And that radically changes the way you live.
Different Masters, Different Life
Because a Christian, v17, is someone who has become ‘obedient from the heart.’ Who and what you’re living for has changed.
Now, Paul knows the illustration of slavery is not perfect. Verse 19, ‘I am speaking in human terms, because of your natural limitations.’ Because however good or kind a human slave master might be, no-one could be as great and as good a master as Christ. As Augustine said, your service is perfect freedom.
But even given the limitations of the image, v19, ‘just as you once presented your members as slaves to impurity and to lawlessness leading to more lawlessness, so now present your members as slaves to righteousness leading to sanctification.’
So it’s not just that the beginnings of these two ways of living that are different - so is the kind of person you end up becoming. The kind of person you’ll be in 5 10, 20 years time. Because give yourself to sin or give yourself to God, and you will become steadily more like what you are, like what you’re giving yourself to.
Imagine that for you it’s control, and you want, you need people to do what you want them to do. And you’re like a dog with a bone - you can’t let go. You have to have your way. If that continues to master you - and people don’t do what you want, what will you become like? You’ll grow steadily more critical and complaining, which will push people away even more, so you’ll complain and criticise more.
Or imagine it’s having the approval of others. Let that master you and when someone else gets the attention - you’ll become more and more resentful; or you’ll become more fragile in the face of criticism - which means your need for approval, your thirstiness and touchiness will grow and grow.
And look at v20: ‘For when you were slaves of sin, you were free in regard to righteousness.’ Which means, when someone continues giving themselves to something other than God, it becomes easier each time and your conscience grows quieter. It begins to bother you less when you click on that thing you shouldn’t, it doesn’t trouble you so much to skip church and head to the mountains,; there’s less and less inner disquiet when you eat, drink, or exercise just that bit too much. Because any hold righteousness might have had on you is slipping. But it will feel good, because you’re free - supposedly. And all the time your conscience is growing harder, and with age it will calcify.
So if you’re not yet a Christian, or even if you think you are but you’re giving yourself to something other than God as your ultimate - ask yourself: what will my soul look like in 10, 20, 30 years from now? Are these choices I’m making causing my love for God and his people to grow, or slowly shrink? Is this thing I’m giving myself to making me more generous and patient, more kind and courageous, more humble and wise, or less? As I allow this thing to dominate my life, is the way I think of and speak of others growing in grace - or criticism? Is my life of prayer and worship increasing, or diminishing?
Because, Paul is saying, when something other than God masters you - it’s a downward spiral of vice, not an upward spiral of virtue.
But there is an upward spiral! Verse 19: ‘so now present your members as slaves to righteousness leading to sanctification.’ And v22: ‘Now that you have been set free from sin and have become slaves of God, the fruit you get leads to sanctification.’
In other words, when you become a Christian, God frees you from slavery to sin, as you respond from the heart to all that Christ is and all that he has done for you. And as you go on doing that - giving yourself to Christ as your master - you steadily grow more like him. Because you always become like what you worship. You always become like what masters you.
Imagine you feel the grip of money. You might be spender or a saver - but you know it wants to master you. How does the gospel free you from its hold? Well, when Paul was encouraging the Corinthians to generosity, did he say: ‘you guys need to be less tightfisted. You need to give more’? No. What did he say? ‘You know the grace of our Lord Jesus Christ, that though he was rich, yet for your sake he became poor, so that you by his poverty might become rich’ (2 Cor 8:9). And as you think deeply about how Jesus gave up his wealth for you, to make you truly rich, and as you let that do its work in your heart, your heart and your hands will open in generosity. You’ll become more like him.
Or imagine you’re struggling with bitterness. Someone’s done something to you and resentment, and unforgiveness, want to master you. What will happen if you let them? If you offer yourself to them? Your soul will slowly shrivel. And it seems the church in Ephesus was dealing with just such a situation, and Paul writes, ‘Forgive one another, as God in Christ, forgave you’ (Ephesians 4:32). I mean, think of all the ways you’ve done against Christ, all the ways you don’t deserve his forgiveness, and yet he forgive you at infinite cost to himself. And as you compare his situation and your situation, you find your heart softening and the desire to forgive growing. You’re becoming just that bit more like him.
Or let’s say you see a newcomer at church - or at least someone you think might be a newcomer. But you’re not sure you can be bothered to walk over, and frankly, you’d rather talk to your friends. And self-centredness is trying to master you - so do you give yourself to it? Not if Christ is your master, because in Romans 15 Paul writes, ‘Welcome one another as Christ has welcomed you’ (15:7). And you remember, ‘hey there was a time when I was an outsider to grace, when I was on the far side of a chasm from God, but in his mercy Jesus reached out to me, and at great cost to himself welcomed me’. And as you do that, it will stir a desire in you to welcome outsiders.
Or maybe you really do want to get your own way on something - but others are standing in the way. And ambition and pride are vying for your heart and frustration is growing. But then you read in Philippians how we should have the mind of Christ, and how he ‘emptied himself, by taking the form of servant’ (Phil 2:7) - literally a slave - and humbled himself to death, even death on a cross - the death of a slave. And you realise, he did it for you. So rather than insist on your own way, you begin to humble yourself, and serve.
And every time you allow the gospel to do its work in your life, every time you give yourself to your new master, you’re becoming more like him. More generous, more forgiving, more welcoming, more humble and more servant hearted.
So Christianity is not: ‘if you want God to love you, you’re going to have to obey and stop sinning.’ It’s: thanks be to God - who has loved me before I did anything to deserve it, and Christ died for me, and rescued me from slavery to sin, and set me free. So now give I’m going to give myself to the one who gave himself for me.
But the differences are not just in this life.
Different Masters, Different Ends.
Because Paul describes the final outcome of giving yourself to things other than God: v21, ‘For the end of those things is death’ And verse 23, ‘For the wages of sin is death.’ So to serve something other than God is a dead end life in this life, and the next. Because there’s always a payback with sin. Sin is always scrupulous to make sure you get the wage you deserve.
But with God, you don’t get what you deserve - because at the cross, Jesus got what you deserve. Verse 23 again, ‘For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord.’
Su and I are currently listening to Homer’s Odyssey - so we can read the real thing before we watch the movie. And every time Homer describes the dawn, he calls it ‘rosy fingered’ - as the colours of dawn extend their hold over the night and extinguish the darkness. And Paul is saying, that is what Christ has done for you. When you become a Christian, it’s a new and rosy fingered dawn. As he sets you free from the penalty and the power of sin, as he brings you into his house, and under his wing. And you and I deserve death, but in Christ he gives us life - in this life and the next.
Sin gives you what you deserve. The Lord Jesus gives you what you could never deserve.
So you’re under grace, not under law - so should you now give yourself to sin? Paul’s answer? By no means!
So this week, when you feel the cold and pale fingers of sin extending over your heart, remind yourself of the gospel - and how the rosy fingered dawn of Christ has dispelled your night. And give yourself to him.
More in Romans
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Freed from the LawJune 21, 2026
The Way to FreedomJune 14, 2026
Christ the Second Adam