(From “Observations on the Divine Attributes”)
God is essentially unchangeable in Himself. Were He otherwise, He would be confessedly imperfect, since whoever changes must change either for the better or for the worse.
Whatever alteration any being undergoes, that being must, ipso facto, either become more excellent than it was, or lose some of the excellency which it had.
But neither of these can be the case with God. He cannot change for the better, for that would necessarily imply that He was not perfectly good before. He cannot change for the worse, for then He could not be perfectly good after that change.
Therefore, God is unchangeable. And this is the uniform voice of Scripture.
Malachi 3:6 declares, “I am the Lord, I change not ” In James 1:17 we read this statement, ”With Him is no variableness, neither shadow of turning.” And in Psalm 102:27, the scriptures declare that God has no end, as we read, “Thou art the same, and Thy years shall have no end.”