Malachi 3:6
“I the Lord do not change.”
The world is a constantly changing place: humans and animals alike change both physically and mentally, even the environment is constantly changing shape and look. Even the entire universe never stays the same: eventually galaxies move, and stars explode. It's a fact of reality everything is either changes or is subject to change therefore nothing stays the same. But even if everything changes one thing will never change but stay the same forever: and that is God.
God through the prophet Malachi says he does not change:
Malachi 3:6
“I the Lord do not change….”
God’s nature does not change:
Hebrews 6:17
“…. God[‘s]…unchanging nature….”
And neither does his will/desire:
Psalm 110:4
“The Lord has sworn(promised)
and will not change his mind”
Numbers 23:19
“God…[does not]…change his mind.”
1 Samuel 15:29
“...He[God]…does not…change his mind…”
Ultimately this means God does not change:
Psalm 55:19
“...God,…does not change…”
So even though the whole universe may change (and it will) God will always stay the same:
Psalm 102:25-27
“...Of old [ancient times] You laid the foundation of the earth, and the heavens…they will all grow old…like a cloak You will change them, and they will be changed. But You are the same…”
God makes it clear that his nature and ultimate desires will never change
This is very good to know! Because it means the personality and nature that we see in God now, will not go away or be changed: he will always be like this forever!