“The Lord is unchangeable in holiness and glory. He is a sun that shineth always with a like brightness.
God, and all that is in God, is unchangeable; for this is an attribute that, like a silken string through a chain of pearl, runneth through all the rest:
His mercy is unchangeable, ‘His mercy endureth forever,’ (Ps. 100:5).
So His strength, and therefore He is called ‘The Rock of ages,’ (Isa. 36:4).
So His counsel, Mutat sententiam, sed non decretum (as Bradwardine); He may change His sentence, the outward threatening or promise, but not His inward decree; He may will a change, but not change His will.
So His love is immutable; His heart is the same to us in the diversity of outward conditions: we are changed in estate and opinion, but God, He is not changed.
1. The more mutable you are, the less you are like God. Oh! how should you loathe yourselves when you are so fickle in your purposes, so changeable in your resolutions!
God is immutably holy, but you have a heart that loveth to wander. He is always the same, but you are soon removed, (Gal. 1:6); ‘soon shaken in mind,’(2 Thess. 2:2); whirried with every blast, (Eph. 4:14), borne down with every new emergency and temptation.
The more you do ‘continue in the good that you have learned and been assured of,’ (2 Tim. 3:14), the more do you resemble the divine perfection.
2. Go to Him to establish and settle your spirits. God, that is unchangeable in Himself, can bring you into an immutable estate of grace, against which all the gates of hell cannot prevail; therefore be not quiet, till you have gotten such gifts from him as are without repentance, the fruits of eternal grace, and the pledges of eternal glory.
3. Carry yourselves to Him as unto an immutable good; in the greatest change of things see Him always the same: when there is little in the creature, there is as much in God as ever: (Ps. 102:26-27), ‘They shall perish, but Thou shalt endure; they shall all wax old as a garment: Thou art the same for ever, and Thy years have no end.’
All creatures vanish, not only like a piece of cloth, but like a garment. Cloth would rot of itself, or be eaten out by moths; but a garment is worn and wasted every day.
But God doth not change; there is no wrinkle upon the brow of eternity; the arm of mercy is not dried up, nor do His bowels of love waste and spend themselves.
And truly this is the church’s comfort in the saddest condition, that however the face of the creatures be changed to them, God will be still the same. It is said somewhere, that ‘the name of God is as an ointment poured out.’ (Song of Solomon 1:3)
Certainly this name of God’s immutability is as an ointment poured out, the best cordial to refresh a fainting soul. When the Israelites were in distress, all the letters of credence that God would give Moses were those, (Exod. 3:14), ‘I AM that I AM hath sent me unto you.’
That was comfort enough to the Israelites, that their God remained in the same tenor and glory of the divine essence; He could still say I AM. With God is no change, no past or present; He remaineth in the same indivisible point of eternity; and therefore saith, I AM.
So the prophet (Malachi 3:6), ἔγω κύριος, οὐκ ἠλλοίωμαι, ‘I am the Lord, that change not’ (or am not changed); ‘therefore ye sons of Jacob are not consumed.’
Our safety lieth in God’s immutability; we cannot perish utterly, because He cannot change.”
–Thomas Manton, “Commentary on the Epistle of James,” The Works of Thomas Manton, Vol. 4 (Carlisle, PA: Banner of Truth, 1871/2020), 4: 113-114. Manton is commenting on James 1:17.