David declares that he will stay away and have nothing to do with people who have a perverse heart. If David was giving this Psalm as his coronation speech, then I suspect this verse means that all the people he will appoint under him will be the type of people who seek God. This does not mean we should only hang out with Christian people or only work with people who believe in God? Obviously, we can't always control whom we are required to be with during the day. The heart of the issue is not whom we have to be with but whether or not we let the lifestyle of those who don't trust in God affect our own lifestyle. Pray for God to give His strength to face that temptation
 Whoso privily slandereth his neighbour, him will I cut off: him that hath an high look and a proud heart will not I suffer.
Verse 5 gives examples of what David meant by the evil people of verse 4. These sins are not the only indications he sees of evil people, but they are just examples.
The first example cited by David is that of slandering one’s neighbor in secret? Why not first mention something more serious like murder or stealing? Murder and stealing are more serious crimes, but slander is a more common problem.
If you were to ask me what sin does the most damage in life, I would say slander. I believe there is more pain caused by slanderous talk than any other sin listed in the Bible. Why is that the case? Most people are honest and do their best not to steal or hurt other people. Yes a “criminal class” does exist and I’m not denying that fact. It is probably easier to have people around us who don’t have a history of stealing or physically hurting other people. However, it is more difficult to stop people from making slanderous accusations, and that is what David is warning against in this verse.
Think about your “world”. What sin is more likely to occur among those we go to church with? Stealing or slander? Even in prayer, we may tend to spread rumors about people and “hide it” by saying we should pray for them. Recognizing and stopping slander should be the duty of all Christians. If someone shares a story with us that is really an accusation, our first response should be, “What did that person say when you confronted them on that issue?"
When the slander spreader says they have never confronted the accused on that issue, you realize that slander has occurred.
There is one more issue at the end of verse 5: “haughty eyes and a proud heart”. This is not something one can see by examining someone’s eyes. Both terms are describing a person who wants to raise him or her self up as opposed to doing what is best for the group or doing what is best for the leader of that group.
Let me explain this another way: If someone asks us to do a task, we have every right to say no, but if we say yes and ignore what is being asked of us, in effect it is a sin because we have put our interest ahead of what we were asked to do. If our leaders decide to complete a task “this way”, having a “haughty eyes” or a “proud heart” means we refuse to humble ourselves to accept that decision.