Doctrine As we explore each of the attributes of God, we quickly realize that one attribute necessarily explains another. For example, God’s eternality has obvious implications for how we understand his immutability or unchangeable nature. Herman Bavinck helpfully overlaps these two perfections (along with others): “Every change is foreign to God. In him there is no change in time, for he is eternal; nor in location, for he is omnipresent; nor in essence, for he is pure being.” 1 The Scriptures frequently refer to God’s unchangeable nature: “For I the Lord do not change” (Mal. 3:6; see also Isa. 14:27; 41:4). Many of these passages refer to his ethical immutability, which denotes his covenant faithfulness to his promises. Such moral unchangeability arises out of God’s ontological immutability, which refers to the fact that he can never change in his being or essence. If God could change, we could never be certain of his promises. Hence, his ontological immutability provides the foundation for his unchangeable promises toward us in Christ. God is what he always was and will be (James 1:17). Because of his simplicity, his eternality demands his immutability. Eternity speaks about the duration of a state, whereas immutability is the state itself. Immutability in God means not only that he does not change but also that he cannot change (Ps. 102:26). God’s immutability provides his people with a great deal of comfort and stability. So, for example, when theologians have historically argued that God is immutable, they have called attention to his unchangeable goodness, love, holiness, power, and wisdom. Do we want a God whose love may change? Do we want a God whose holiness can change? Do we want a God whose power may change? What a blessing to affirm God’s immutability. If we apply God’s eternality and immutability to his knowledge, then we have to say that God knows all things at once. Immutability precludes change in God’s knowledge. In addition, because he is spirit, God is not subject to mutations that belong to those with bodily natures. The Puritan Thomas Vincent aptly summarizes the several ways that we are to understand how God is unchangeable: 1. God is unchangeable in regard to his nature and essence (Ps. 102:25–27 ). 2. God is unchangeable in regard to his counsel and purpose (Isa. 46:10). 3. God is unchangeable in regard to his love and special favors (Rom. 11:29; James 1:17). 2 God’s immutability regarding his promises and purposes provides great comfort: “God is not man, that he should lie, or a son of man, that he should change his mind. Has he said, and will he not do it? Or has he spoken, and will he not fulfill it?” (Num. 23:19). His promise that all things work together for the good of those who love God (Rom. 8:28) would be jeopardized if he could change in his purposes toward us. Indeed, God’s immutable promises and purposes toward Christ afforded assurance even for him (e.g., John 17), but that assurance would have been lost if God could change.