Immutability is the truth that God does not change. He is the same today as He was a thousand years ago: “I, the LORD, do not change,” and Jesus Christ is the same yesterday, today and forever. The lesson adds that only two things remain unchangeable, God and His Word, and the two cannot be separated. Human beings, by contrast, are changeable in mood, promise and goodness, and everything in the universe, from galaxies to the smallest objects, is passing away.
The study then asks why this matters. If God’s words were unstable, we could not rely on anything He has promised, and a promise of salvation could one day be withdrawn. Because He does not change, our hope is a sure and steadfast anchor. The God who is our refuge and strength stays with His people, and His word endures forever.