The practice and proof of righteousness

John wants his beloved spiritual children not to be deceived by those who claim righteousness in the heart but show none in the life. He emphasises the Lord Jesus as the standard of righteousness, the Man who showed love to God and to men in all his life. He underscores the fact of righteousness, that a Christian is righteous just as Christ himself is righteous. So what is the proof of that righteousness? It is doing righteousness, it is living out one's union by faith with the Lord Jesus.