Isaiah 64:5 speaks to God, saying, “You were angry when we sinned; you hid yourself when we did wrong” (Common English Bible).
It took me a long time to come to terms with the idea of God’s anger. In my own faith, the most helpful idea here is that God is slow to anger. If we forget that God is slow to anger, then God is reduced to a cruel monster out to get us. If we forget anger altogether, then God is reduced to a puppy dog who wants to lick our face no matter what terrible things we continue to do. Both God-the-monster and God-the-puppy-dog are idols: images of God that don’t match what the Bible says.