After the psalmist gives a general accusation in verse 17, he now goes on to list the violations that prove the accusation. The Israelite's hypocrisy is simply the fact that they loved what God hated. These violations include theft, adultery and false accusation against their fellow man.
Practically, for today's Christian, these three verses give examples of what these "church pew sitters" are like. In other words, how do I know if I am truly committed to God or if I am just going through the motions of going to church? The answer is to look at these verses. If they "fit", then one is not truly committing their lives to God.
In seeking to help such an individual, ask God to give you wisdom and understanding. Be careful in your approach, all the while understanding God has forgiven you and now we ask that He help us with others.
After all, there are really only two kinds of people: saved sinners and lost sinners. Althought the saved sinner will still sin, he makes every effort not to sin as he has repented and turned from his sin. Let's give the world around us a clear picture of who Jesus is to us.