The concept of sin is going our way, not God's way, because we know better, we're more important. In chapter five verse one and two, we can see that it is Jesus who provides the standard. He is the one true example of righteousness and holiness. This is what love is all about. It is this other person centred love that is the basis of the unity of believers in the body of Christ.
Selfishness has no place in the Christian worldview.
So now in verse 25 Paul gets specific. He tells us not to speak falsely to each other. If we are in Christ, living together as one body, the church, with Christ as the head, then we'll only be lying to ourselves. Satan must really be sitting back and enjoying the show to see the body of Christ trying to self-destruct. Having an other person focused love as a starting point is a key element.