God's Immutability

²⁵ Of old you laid the foundation of the earth, and the heavens are the work of your hands. ²⁶ They will perish, but you will remain; they will all wear out like a garment.

You will change them like a robe, and they will pass away, ²⁷ but you are the same, and your years have no end. Psalm 102:25-27

“For I the Lord do not change...” Malachi 3:6

I. God is unchanging in His being.

... the earth, and the heavens are the work of your hands. They will perish, but you will remain; they will all wear out like a garment.

You will change them like a robe, and they will pass away, but you are the same, and your years have no end. Psalm 102:25-27

II. God is unchanging in His perfections

“Every good gift and ever perfect gift is from above, coming down from the Father of lights, with whom there is no variation or shadow due to change.”

James 1:17

III. God’s Word is unchanging

Forever, O Lord, your word is firmly fixed in the heavens. Psalm 119:89,

All your commandments are true. Long have I known from your testimonies
    that you have founded them forever. Psalm 119:151-152

...All flesh is grass, and all its beauty is like the flower of the field...The grass withers, the flower fades, but the word of our God will stand [for how long?] forever. Isaiah 40:6, 8

“What God declares to be true was true from the beginning and always will be. So, His ancient Words remain our infallible guide despite the passing of time and the changes in human culture.” - John Frame

IV. God is unchanging in His plans

“The counsel of the Lord stands forever, the plans of his heart to all generations.” Psalm 33:1

Remember the former things of old; for I am God, and there is no other; I am God, and there is none like me, declaring the end from the beginning and from ancient times things not yet done, saying, ‘My counsel shall stand, and I will accomplish all my purpose...I have spoken, and I will bring it to pass; I have purposed, and I will do it.’

Isaiah 46:9-10, 11b

“God is not man, that he should lie, or a son of man, that he should change his mind.” Numbers 23:19

V. God is unchanging in His promises

“For I the Lord do not change; therefore you, O children of Jacob, are not consumed.” Malachi 3:6

For the mountains may depart and the hills be removed, but my steadfast love shall not depart from you, and my covenant of peace shall not be removed,”
  says the Lord, who has compassion on you. Isaiah 54:10