Immutability is an attribute which God claims for Himself. "I am the LORD I change not" (Malachi 3:6). He never undergoes any sort of variation – not in His person, not in His perfections, not in His purpose, not in His power, and not in His promises. All His creatures change. "They shall perish, but Thou shalt endure: yea, all of them shall wax old like a garment; as a vesture shalt Thou change them, and they shall be changed: but Thou art the same, and Thy years shall have no end" (Psalm 102:26-27). Our lives are made up of an endless series of changes: from childhood we grow to youth, from youth to adulthood, from adulthood to old age, and from old age we exit this world into eternity. Change is a part of our lives, but not with God. Bless His Name, with Him "there is neither variableness, neither shadow of turning" (James 1:17).
What does this doctrine mean for us? Here is where ransomed sinners can find hope and confidence, in the Lord who will never change! His love and mercy will never change. His covenant of grace, made with Christ, will never change. Even the fall of Adam did not alter either the purpose or the love of God for His people. Actually, the fall gave God the opportunity to express His unchanging affection for His people in providing a Sacrifice and Substitute to put away our sins. Herein lies our assurance. Though we are fickle, changing pilgrims, walking in faith today, staggering in unbelief tomorrow, our Lord is always faithful and always the same. The Lord is faithful "To perform the mercy promised to our fathers, and to remember His holy covenant" (Luke 1:72). He who loved us in old eternity, who gave His Son up to divine justice to put away our sins, will always remember His covenant and be faithful and true to His Word. "He is faithful and just to forgive us our sins" (1 John 1:9). The Lord was pleased with the redemptive work of Christ and, being a never-changing God, will always accept us for Christ's sake. "If we believe not, yet he abideth faithful: He cannot deny Himself" (2 Timothy 2:13). The Lord cannot do anything contrary to His nature and perfections – He cannot change – therefore, our salvation is secure!