Yes, their tongue is suggestive of whether or not their heart is right with God. For surely if one curses the Lord's name and or others is not loving God and loving others as a person who is born again of the Spirit.
Are you saying now that you are unsure of in where he stands?
Romans 7 is Paul speaking from the perspective before he was a Christian. In
Romans 7:14, Paul says he is carnal and he is sold under sin. Which would be a contradiction if he were to say this as a believer in Jesus Christ because he says in
Romans 8:2, that the law of the Spirit of life in Christ Jesus has made him free from the law of sin and death.
As for repenting of good works: Well, if one's work is God's work or Christ's work moving within the believer, then there is nothing to repent of. For a true believer will bring forth the fruits of the Spirit within their life.
As for my bring up of
1 John 3:15 in regards to
1 John 4: Well, I can't see how you can write that one off. Either way you slice it, we cannot hate our brother otherwise we will not have eternal life abiding within us.