Does God change his mind? The answer is a yes and no. There are decrees that God makes that are unchangeable. God never changes his mind about these things. No amount of prayer or pleading will get God to change his mind. Probably the best example are moral values and decrees. If you pray and ask God to change his mind about adultery, or lying, or stealing, or blasphemy, you can be completely assured that he will not change his mind about these things. They are wrong and will always be wrong. These are fixed decisions by God.
But, there are things that appear to us to be God changing his mind. For instance, God tells Moses he will destroy Israel and make a new nation from him. Moses pleads with God and God decides to forgive (Numbers 14:12 and Deuteronomy 9:14).
In reality, God is not changing his mind as if he decided one thing then suddenly had a new and better thought he didn’t have before and presto, he changes his mind. This doesn’t happen with God because he is eternal and knows all things from eternity past to eternity future. However, there is one way God appears to change his mind. It is when we make a choice, either good or bad, and God appears to react to that choice. There is a perfect statement about this very thing in Jeremiah 26:13. “Now therefore amend your ways and your deeds and obey the voice of the Lord your God; and the Lord will change His mind about the misfortune which He has pronounced against you.” Here we see that God is willing to change a decision based upon what we do. Repentance changes God’s decisions within the framework of his ethics. This is why, in the book of Jonah, God did not destroy Nineveh. The city repented so God relented. In fact, that’s a good statement to remember. When we repent, God relents.
Now, because God is all knowing he knows if we will not repent so in that case God’s decision is fixed. But it is also fixed if we repent. The issue before us then is how we will respond to God when he confronts us about our sin? If you don’t believe in Jesus Christ, then God’s decision of wrath against you is fixed. “Whoever does not believe is condemned already” (John 3:18b). But if you turn your direction and will follow Jesus, everything changes. “Whoever believes in him is not condemned” (John 3:18a).
Knowing that God never changes should bring us great comfort and assurance. “Jesus Christ the same yesterday, and today, and forever” (Hebrews 13:8). We can know without any doubt that God is merciful if we repent. We can know that his love is never lifted from us. “Nothing can ever separate us from God's love” (Romans 8:38). Imagine if he were a god who changed his mind willy nilly. What a terrifying position we would be in, never having any assurance of God’s love for us. Thankfully, this is not the case. God’s character is predictable, and in that we can rest.