The Unchangeability or Immutability of God is an attribute that "God is unchanging in his character, will, and covenant promises."

The Westminster Shorter Catechism says that "[God] is a spirit, whose being, wisdom, power, holiness, justice, goodness, and truth are infinite, eternal, and unchangeable." Those things do not change. A number of Scriptures attest to this idea (such as Num. 23:19; 1 Sam. 15:29; Ps. 102:26; Mal. 3:6; 2 Tim. 2:13; Heb. 6:17–18; Jam. 1:17)

God's immutability defines all God's other attributes: God is immutably wise, merciful, good, and gracious: Primarily, God is almighty/omnipotent (having all power), God is omnipresent (present everywhere), God is omniscient (knows everything), eternally and immutably so. Infiniteness and immutability in God are mutually supportive and imply each other. An infinite and changing God is inconceivable; indeed, it is a contradiction in definition.