Did God take on a human nature at a particular time in history according to the Bible? God was once not a descendant of Adam, now some of Him is. That is a change.
Was the Son always in flesh, bone, soul and spirit seated on the throne of heaven? That's a change.
Wrong-
Immutability is an attribute which God claims, and challenges as peculiar
to himself;
"I am the Lord, I change not" (Malachi 3:6).
Mutability
belongs to creatures, immutability to God only; creatures change, but he
does not: the heavens and the earth, which he has made, are not always
the same;
but "he is the same forever": the visible heavens are often
changing; they are sometimes serene and clear, at other times covered
with clouds and darkness, and filled with meteors, snow, rain, hail, etc.
the face of the earth appears different at the various seasons of the year,
and is particularly renewed every spring: it has undergone one great
change by a flood, and will undergo another by fire; when that, and "the
works that are therein, shall be burnt up; and the heavens, being on fire,
shall be dissolved; and the elements shall melt with fervent heat"; and
"new heavens", and "a new earth", shall succeed (2 Peter 3:10,12,13),
to
which changeableness in them, the unchangeableness of God is opposed:
"All of them shall wax old like a garment, as a vesture shall you change
them, and they shall be changed: but you are the same, and your years
shall have no end" (Psalm 102:25-27).
The sun in the firmament, that
great luminary, and fountain of light and heat, in allusion to which, God
is called "the Father of lights", has its parallaxes, or various appearances,
at morning, noon, and evening; it has its risings and settings; and never
rises and sets at the same point in the heavens one day in the year, but
always varies a little; it is sometimes under clouds, and in an eclipse; but
"with" God "is no variableness", parallagh, or a parallax; the sun, at
certain seasons of the year, passes from one tropic, and enters into
another, as well as casts shades on the earth; but with God there is "no
shadow of turning", trophv, of a trope, or tropic; there is no mutation nor
turning in him, nor shadow of any (James 1:17; Job 23:13),
the
inhabitants of Heaven and earth are changeable, even the most excellent
of them, angels and men: angels in their original nature and state, were
subject to change, as the apostasy of many of them have shown; who have
changed both state and place; they "kept not their first estate, but left
their own habitation", being obliged to the latter, because of the former;
for sinning against God, they were hurled out of Heaven, and "cast down
to Hell, and delivered into chains of darkness, to be reserved unto
judgment" (Jude 1:6; 2 Peter 2:4), the angels which stood when the rest
fell, are now indeed become impeccable, and are firmly settled in their
state of integrity; but then this is owing not to their own nature, but to the
electing grace of God, in Christ, and to the confirming grace of Christ,
their head, who is the "head of all principality and power" (1 Timothy
5:21; Col 2:10).
Man, at his best estate, his estate of innocence, and integrity, was
"altogether vanity": for though not sinful, yet being mutable, and left to
the mutability of his will, which was his vanity, when tempted fell into
sin; and though made upright, lost the rectitude of his nature; though
made after the image of God, soon came short of that glory; and though
he had dominion over the creatures, being in honor, he abode not long,
but became like those he had the power over; and though placed in the
most delightful and fruitful spot in all the globe, yet, rebelling against his
Maker and Benefactor, was driven out from thence by him; and is now a
creature subject to innumerable changes in life; diseases of various sorts
seize his body, and change his beauty and his strength, and death at last
turns him to corruption and dust; he is like the changeable grass of the
field; flourishes a while, is then cut down, and withers away; but God and
his "word endure forever" the same (1 Peter 1:24, 25), good men are very
mutable, both in their inward and outward estate: in spiritual affairs; in
the frames of their minds, in the affections of their souls, in the exercise
of grace, in their devotion and obedience to God, and worship of him: in
temporal affairs; what an instance of mutability was Job, in his estate, in
his family, and in his health and friends? well might he say, "changes and
war are against me" (Job 10:17)
You ask the wrong questions-from a open theism's worldview.