Do not lie to one another, seeing that you have put off the old self with its practices  and have put on the new self, which is being renewed in knowledge after the image of its creator.
Here is the common argument: Christianity is just about rules, rules and more rules. So in our text we have “do not,” “put off,” “put on,” or putting it another way don’t do that, do this!
In fact some feel when they read the previous verses in Colossians chapter 3 where Paul says, put to death sexual immorality, impurity, passion, evil desire, and covetousness, which is idolatry. Put away anger, wrath, malice, slander, and obscene talk from your mouth it’s another long list of “must not’s.”
The fact is, Paul does also provide, later in the chapter, a more positive approach to faith like compassion and kindness and humility and how we relate in marriage, family, in fact our relationships with just about everyone.
So why the list of rules, or apparent rules? And also what’s the difference between what Paul has previously said in chapter 2 and what he says here in chapter 3.
Paul had spoken quite harshly of those in Colossae who insisted on strict behaviour when it came to such matters as what they ate and drank, as well as the following of certain religious festivals. The false teachers insisted on a rigorously austere lifestyle , always quick to say, “Don’t handle that! Don’t taste these! Don’t touch those!” (Colossians 2:21).
So what makes Paul’s rules so different from theirs? How is Paul’s view of following Christ an improvement on theirs, isn’t it much the same?
He has “do’s and don’ts”, they have “do’s and don’ts” so how does one avoid falling prey to the legalistic mentality that Paul so firmly denounces? How do we pursue holiness without reducing Christianity to a moral code of living by rules.
As a child growing up in a Christian home, we had our Sunday rules; No TV, no radio, no going out to play, wear your best clothes. Read only books related to the Bible and so on. Did I break them, of course I did, in fact I found elaborate ways to break them. Leaving my school books at a friends house so I needed to go out to get them back and in so doing could watch his TV was one. We all know rules are easily breakable if you want to.
The answer to the question is, the difference found in something Paul repeatedly emphasises in chapter 3 that is noticeably absent from the man-made philosophy threatening the church in Colossae.
Let me explain. The legalists argue that if you don’t do this and you do do that then you will gain favour with God and you will be let’s call it “better.”
Paul, along with other NT writers argues differently. We already have the favour of God and that favour is never removed or diminished. It is given according to his Grace and not by our works, and because of this favour and Grace we delight in expressing holiness. It is not duty but delight.
We are not encouraged to do this or avoid that in order to gain Christ. Rather, it is because we have already died with Christ (Colossians 2:20) and have already been raised with Christ (Colossians 3:1) that we avidly seek after holiness. Put simply we fight sin and pursue purity not in order to find status or acceptance but because our lives are already hidden with him (Colossians 3:3).
This is seen very clearly in our text. Paul says do not lie, because we have already put off the old self and put on the new self, which is being renewed in knowledge after the image of its creator. It does not stop there, look at chapter 3 verses 12 and 13.
It is also BECAUSE we are “God’s chosen ones, holy and beloved” that we are to be compassionate and kind and humble, etc. And it is BECAUSE we have already been fully and freely forgiven by Christ that we “also must forgive” one another.
So, we “put to death” and “put off” such practices because we have already discarded the old man and his ways and have put on the new.
Paul says a similar thing to the church in Ephesus in Ephesians 4. There he commands the believer “to put off your old self” and “to put on the new self.” If you ask yourself the question why, then Paul tells you why in the 3 previous chapters. Let me give you just a few reasons.
He chose you before the foundation of the world (1:1)
He predestined us for adoption (1:4)
In him we have redemption (1:7)
In him we have obtained an inheritance (1:11)
You were dead in the trespasses and sins (2:1)
But God being rich in mercy, because of his great love (2:4)
By Grace you have been saved (2:5)
We are new people working to become in practice what God has already made us, and that involves the resolve to put off the old way of life as it attempts to impinge on what we have received in Christ.
Here again we see the tension between the “already” and the “not yet” in Paul’s theology. We have “already” put off the old man but we have “not yet” grown into a life of consistency with that new identity.
The bottom line then is this: There is a world of difference between working to attain a life, than living out a life already graciously and mercifully given.
So by grace we are striving to become the new man we already are.