Immutability.
Three things are said to be unchangeable: God's counsel, His word, and His oath. Hebrews 6:17, Hebrews 1:6. To these certainty may be attached. In Malachi 3:6 we read, "I am Jehovah, I change not," and the Lord is "the same yesterday, and to-day, and for ever." Hebrews 13:8.