‘Put on therefore, as God's chosen ones, holy and beloved, a heart of compassion, kindness, humility, meekness, longsuffering, forbearing one another and forgiving each other. If any man have a complaint against any, even as the Lord forgave you, so also do you.'
Having described the old man in terms of his behaviour he now describes the new man which they are to ‘put on', in the same terms. ‘Put on'. That is, they must allow the new, spiritual life within them to take over the rule of their lives. They are to submit to the Spirit (compare Galatians 5:16-18).
‘Chosen ones, holy and beloved.' This is spoken to those who have been ‘chosen by God', and as a result have been drawn to Jesus Christ (John 6:44). They are ‘holy' because they have been set apart in Christ (1 Corinthians 1:2), Who has been made to them sanctification (holiness) (1 Corinthians 1:30), setting them apart to God and making them acceptable in His presence and they are beloved because they are engraced in the Beloved (Ephesians 1:6).
With this encouragement he outlines what kind of people they are to be. From the heart, for a forced pretence is of no value, they are to reveal compassion, kindness, consideration for others, a willingness to humble themselves, a willingness not to fight for their own position and honour, a willingness to bear with the weaknesses of others, a willingness to ‘bear all things, believe all things, hope all things, endure all things' (1 Corinthians 13:7), and a willingness to forgive.
This last is emphasised by repetition. If they have anything against another they are to forgive them just as ‘the Lord' has forgiven them. If the One Who is ‘the Lord' is willing to forgive, surely they too should be willing to forgive those over whom they are not Lord (there may be here in this reference to ‘the Lord' in connection with forgiveness, the influence of Jesus Christ's parable recorded in Matthew 18:27).
But note that this is not a blanket forgiveness regardless of the attitude of the person forgiven. God forgives us when we repent, and Jesus makes clear that our forgiveness should be in the light of repentance. ‘If your brother sins against you, rebuke him, and if he repents forgive him' (Luke 17:3), for true forgiveness reinstates the one forgiven and that requires that he recognise his fault.
Thus overall they are to be Christlike because He lives in them and through them.
(Some authorities have ‘Christ' here instead of ‘the Lord' but the latter has by far the strongest support and adds greater emphasis to the argument.