Immutability means that God does not change in regard to his attributes or his promises. This is sometimes referred to as God’s constancy. This attribute is often confused to mean that God cannot change his direction or his feelings. But this is not the case. God’s direction can change (e.g. the Old Covenant to the New Covenant), and his feelings can change. However, God’s feelings never affect or manipulate his decisions. Several passages teach the immutability of God:
(1 Sam. 15:29) Also the Glory of Israel will not lie or change His mind; for He is not a man that He should change His mind.
(Mal. 3:6) For I, the LORD, do not change; therefore you, O sons of Jacob, are not consumed.
(Ps. 33:11) The counsel of the Lord stands forever, the plans of His heart from generation to generation.
(Jas. 1:17) Coming down from the Father of lights, with whom there is no variation or shifting shadow.
(Num. 23:19) God is not a man, that He should lie, nor a son of man, that He should repent; has He said, and will He not do it? Or has He spoken, and will He not make it good?
(Heb. 6:17) In the same way God, desiring even more to show to the heirs of the promise the unchangeableness of His purpose, interposed with an oath.
(Heb. 13:8) Jesus Christ is the same yesterday and today and forever.
What about times in the Bible where God seems to change his mind?
God’s promises are true regardless of my feelings. God works independently of our feelings or intuition. Whether I am on my best day or my worst, God’s promises don’t change.
God is constant and not capricious. He doesn’t change—even if life and circumstances do. He is dependable and a sturdy foundation for life. Everything good about God could someday change if it weren’t for this attribute.
 The view that God doesn’t change his emotions is not immutability, but impassibility. We reject this view based on biblical revelation. Herman Bavinck expresses this view: “Those who predicate any change whatsoever of God, whether with respect to his essence, knowledge, or will, diminish all his attributes: independence, simplicity, eternity, omniscience, and omnipotence. This robs God of his divine nature, and religion of its firm foundation and assured comfort.” Herman Bavinck, Reformed Dogmatics, 2:158.