(Francis Turretin, highlights)
When we say that God is immutable, we mean that God does not change.
He does not change:
in His being (what He is),
in His attributes (who He is),
in His purposes (what He plans),
or in His promises (what He has spoken).
God is always the same—perfect, complete, and unchanging.
“For I the LORD do not change.” (Malachi 3:6)
Change belongs to creatures, not to the Creator.
Turretin reasons carefully that immutability necessarily belongs to God.
Change is either:
from worse to better, or
from better to worse.
But
God is already perfect.
He
cannot improve, and He cannot decay.
If God could change, it would mean He was once imperfect or could become so—both are impossible.
“Be perfect, as your heavenly Father is perfect.” (Matthew 5:48)
God is not becoming something—He simply is.
Creatures
change because they move from potential
to
actual.
God
has no
potential—everything
in Him is already fully actual.
That is why God says:
“I AM WHO I AM.” (Exodus 3:14)
God does not grow, develop, or adjust. He simply exists eternally as He is.
Change
requires time.
But
God is eternal,
not bound by time.
Past,
present, and future are all equally
present to God.
Therefore,
there is no moment in which God becomes something He was not before.
“With whom there is no variation or shadow due to change.” (James 1:17)
Turretin stresses that God is simple, not composed of parts.
Things made of parts can change when:
parts are added,
removed,
rearranged.
God
has no
parts.
His
attributes are not pieces of Him—they are identical
with His being.
So if God changed, His very essence would have to change—which is impossible.
Scripture sometimes speaks of God as repenting, relenting, or changing His actions (e.g., Genesis 6:6; Jonah 3:10).
Turretin makes an important distinction:
God’s eternal decree never changes.
But God changes how He acts toward people when their situation changes.
Example:
God eternally willed: If sinners repent, I will spare them.
When they repent, God spares them.
The people changed, not God.
These
passages speak in
human language,
so we can understand God’s dealings.
They describe a change in
relationship,
not a change in God’s
nature or purpose.
“God
is not man, that he should lie,
or a son of man, that he should
change his mind.” (Numbers 23:19)
God does not experience emotions the way humans do.
He is not:
surprised,
frustrated,
emotionally overwhelmed.
Yet Scripture truly teaches that God:
loves,
hates evil,
shows mercy,
expresses wrath.
Turretin explains:
These are not emotional fluctuations in God.
They are constant, holy dispositions expressed in different ways depending on the object.
God’s
love is always love.
God’s justice is always justice.
What
changes is how
creatures experience Him,
not what God is.
Far from making God cold or distant, His immutability is a great comfort.
If God could change, His promises could fail.
But because He does not change:
His covenant stands,
His Word remains true,
His grace does not expire.
“The counsel of the LORD stands forever.” (Psalm 33:11)
Human
love rises and falls.
God’s love does not.
Those whom God loves in Christ are loved:
freely,
eternally,
unchangingly.
“Having loved his own who were in the world, he loved them to the end.” (John 13:1)
If God changed, salvation would rest on something unstable.
But because God is immutable:
election is secure,
justification stands,
glorification is guaranteed.
“The gifts and the calling of God are irrevocable.” (Romans 11:29)
God does not change because He is perfect, eternal, simple, and fully actual.
Scripture passages that seem to show change describe God’s actions, not His essence.
God’s will is unchanging, though His works vary according to His wise plan.
God’s immutability is not a problem—it is a foundation of faith, comfort, and assurance.
An unchanging God is the only safe God to trust.
“Jesus Christ is the same yesterday and today and forever.” (Hebrews 13:8)