The concept of God implies perfection. And perfection cannot change because then it would become imperfect. God is immutable in every way. God is immutable in his essence. God is immutable in his characteristics as God. When God speaks, that word is immutable. When God is powerful, that power is immutable. When we talk about God's wisdom, that wisdom is immutable precisely because it belongs to God, and God is perfect. God is eternal, the same from eternity to eternity. The attributes of God are all immutable. When we think of a mutable or changeable being, we are no longer thinking about the Creator. We are no longer thinking about God. We are thinking of a creature. The creature is the one who changes, changes when she gets old, changes because he is not perfect, changes because we can improve. When we exist or believe or think something, since we are creatures, we can improve in the future, and therefore, change to improve. But God is perfect. He does not need to improve. He cannot improve. It is not only that he is immutable. He cannot change because, by virtue of being God, he is a perfect being in himself, independent of everything, not dependent on anybody. Nothing affects him. Nothing transforms him. Nothing changes him. He does not age. He exists outside of time and space. He is a being without comparison, set apart, and therefore, we can only talk about the immutability of God. So, regarding the question: How is God immutable? In every way that we can think of God, God is immutable. His decrees are immutable. His word is immutable. His essence, as we said, is immutable. His Spirit is immutable because he is God, and God by definition is immutable. God has not become immutable. He is: "I AM WHO I AM" and always will be. In God's case, what he once was, he is today. What he once thought, he thinks today, and he will think the same tomorrow, because everything God conceives is perfect. Therefore, he doesn't have the need to change opinions tomorrow, or change his being, or change his methodology, because from day one he thought of everything immutably; he thought of everything perfectly.