There are not many times in scripture where we are actually told it is okay to "hate" something, but when we are given this instruction it usually has something to do with evil or bad stuff. For example, in both Exodus and Deuteronomy we are told God hates it when his kids worship other gods. It doesn't say we are to hate worshipers who worship other gods, but that God hates this behavior in his kids. In Deuteronomy 23, the Israelites were given specific instructions not to hate two groups of people - the Edomites and the Egyptians. The Edomites were actually their relatives and the Israelites had actually spent time dwelling in the land of the Egyptians. Hatred toward these two people groups was actually instructed against. We are also told that God hates people who cheat (use false weights) in order to take advantage of another individual. Psalm 5 tells us God hates those who make secret plans to hurt others. In fact, God tells us it is really all right to "hate" anything which leads people the wrong way. In other words, we are to be unwilling to embrace or accept those things which lead people down paths of destruction. Instead, we are to live as positive examples of his love and be those who direct (through both the example of our lives and the words of our mouth) others to follow in paths which lead to the best outcomes for their lives.
Hate evil, you who love the Lord. He protects his followers and saves them from evil people. Light and happiness shine on those who want to do right. Good people, be happy in the Lord! Praise his holy name! (Psalm 97:10-12 ERV)
We often see David recounting this teaching in his own life. He pointed out the pathway of the ungodly (those who have not yet said yes to Jesus in their lives) as leading to destruction. This path is something he often spoke of "hating" - because in refusing to do what God says, they were choosing to live outside of God's grace and this was dangerous territory for them. There were times when he would express his frustration of how long he had to put up with people who hated to follow after peace in their own lives and the life of others. Why? The friction and tension created by this "hatred of peace" is destructive in any community. It tears down fragile hearts and puts up walls of hatred which are harder to bring down later on in life.
Solomon recounted the things God hates to see in the lives of his kids - because those things tear us down, create division in the community of faith, paint a negative testimony of God's grace to those who don't understand much about God, and give us grief beyond what we may want to be dealing with down the road. There is one passage in Proverbs which pretty well sums it up: To respect the Lord means to hate evil. I hate pride and boasting, evil lives and hurtful words. (Proverbs 8:13 ERV) Hatred is the opposite of respect, is it not? Hatred causes a repulsion, respect draws us together. To respect the Lord means we come to a personal place of hating evil - first in our lives and then in the world around us.
When we develop the "right attitude" toward evil (that which is morally wrong), then we are more likely to avoid heading in the direction of evil! This is the purpose of Solomon's instruction to "hate evil" - to avoid its path. The pathway of evil leads to destruction - suffering and disaster leave many lives riddled along its pathway! When we "want" to do right, God is faithful to help us do right. When we develop a healthy "hatred" of evil in our own lives, God is pleased to come alongside to help us steer clear of those things which will bring decay, ruin, and injury into our lives. Some call "evil" a force of nature that just gives rise to wickedness and sin. They are not far from the truth on this one. It is within our "nature" to pursue some of the most harmful stuff. This should give us a clue that we need help to get our "nature" turned around so as to not be as "inclined" toward those things which only bring harm to us and others around us.
All action begins with the determination of thought which says we no longer want to pursue the particular path we are on, or that we desire to follow a new path marked out for us. Since action begins in thought, we need God's help to purify our thoughts - pointing out to us those thought patterns which are harmful, hurtful, and bordering on producing "evil" (actions which are morally wrong). As he does this, we must be willing to lay down these oftentimes "long-held" beliefs, patterns of thinking, and memories. They are what is bringing "decay" into our lives, so ridding ourselves of these thoughts is what can actually help to bring health into our minds and positive actions into our daily walk. Even the smallest amount of decay in a tooth had the capability of destroying not only the tooth where it has taken hold, but those teeth around it, and then far into the gums, and even into the entire person's bloodstream! Who knew a tiny bit of decay had this much harmful potential? I think God does! This is why he gives us this instruction to hate evil - it has a "decaying potential" far beyond what we may believe possible. Embrace even the tiniest bit and we are opening ourselves up for what could become a "systemic problem" in our lives! Just sayin!