Whenever we talk about God’s immutability, someone always says, “Wait a minute. The Bible talks about God changing His mind. In fact, He changed His mind about destroying Israel after Aaron built the golden calf.”

That’s true as far as it goes. The Bible does say that God was going to destroy the people for their sin (Exodus 32:10). But Moses pleaded with God not to do it, “so the lord changed His mind about the harm which He said He would do to His people” (v. 14). So we’ve got a problem here. If God doesn’t change, how can He change His mind?

Although God’s character does not ever change, Hid methods may. Here’s what I mean. God’s character is constant; however, if a change on man’s part affects another part of God’s character, God is then free to relate to that person out of that part of His character rather than out of the previous part of His character. For example, God was going to destroy Nineveh because of its sin. When the people there repented, God did not change His mind about sin. In their repentance they appealed to another part of God’s character, His grace. God had been dealing with them from one part of His character, His wrath against sin. Now their repentance brought them another part of His character.

By the way, God has given us proof that He will never change: the rainbow. The rainbow was God’s promise to Noah the He would never destroy the earth by water again. Destroying mankind in the flood hurt God so badly the He said, “I’ll never do it again, and to let you know I’ll give you a rainbow as a sign in the heavens.” Every time you see a rainbow, you need to say, “Thank You, Lord. You don’t change. You are constant.” God is immutable. He does not change.

Excerpt from: Theology You Can Count On by Tony Evans