If we are in Christ, we are under a different standard. No longer are we following the rules for the sake of the rules, but for the sake of Christ. Living in harmony with others isn't about looking like a good person, it's about recognizing the life of Christ and aligning ours with the help of the Holy Spirit. This is the reason that sin cannot live in us. Not because we should be flawless, but be cause the moving of the Spirit and the example of Christ should make it unfit to live in us.