God is unchangeable

God is an unchangeable being, not only without, but incapable
of the least alteration. He is the same yesterday, to-day,
and for ever, Heb. xiii. 8. He is what he was, and what he will
be eternally. He is the same since the world was made that he
was before the world, and that he will be when this world shall be
no more: ‘With him is not the least variation, or shadow of turning,’
James i. 17.

When Grod hates those angels as apostates, whom first he loved,
as created pure and holy, he is still the same; the change is not
in God, but in them. Bring clay to the sun, it hardens it; bring
wax to the sun, with the same influence, it softens it, without any
alteration in the sun. When God punisheth a man that is wicked,
and prospereth the same man becoming a penitent, he is still the
same. If a man walk on one side of a church, the pillars are on his
left hand ; if on the other side, on his right hand. The pillars
remain where they were, the motion or change is in the man.

But creatures are all mutable. The old heavens will pass away, and
new ones succeed in their room at the general conflagration, but the
God of heaven will never pass away. Man is ever in motion, from one
condition to another. His body changeth in its age, constitution, temper;
at last into rottenness, dust and corruption : ‘I have said to corruption,
thou art my father ; and to the worms, ye are my brother and sister,’
Job xvii. 14. His soul changeth in its passions, affections ; love,
hatred, delights, desires : his whole man changeth in its place, company,
carriage, conversation : he hath no consistency while he is, he continueth
not what he was. Job xiv. 2, 3. Angels are changeable ; even the good angels,
though not as men, yet as creatures ; as perfect as they are,
they have this imperfection.

1. They are who once were not, and, in regard of themselves, have a possibility
not to be.
2. Angels may lose what they have, and attain what they have not.
3. Angels are mutable in regard of place, sometimes in heaven, sometimes
on earth. What little unchangeableness is in angels, is derivative,
God is the original of it ; their immutability at most is but
from their creation, I suppose some time since ; for the good angels
as well as bad were created mutable, but God’s immutability is
from eternity. The whole world indeed is a sea of glass, Rev. iv.6, always
ebbing and flowing, never at a stay ; but the maker of the world may well
say, ‘I the Lord change not,’ Mai. iii. 6.

George Swinnock, The Incomparableness of God