This comes from Stephen Charnock at puritansermons…

An extract from The Chief of Sinners Saved

The insufficiency of nature to such a work as conversion
is, shows that men may not fall down and idolize their own wit
and power. A change from acts of sin to moral duties may be done
by a natural strength and the power of natural conscience: for
the very same motives which led to sin, as education, interest,
profit, may, upon a change of circumstances, guide men to an outward
morality; but a change to the contrary grace is supernatural.

Two things are certain in nature. (1.) Natural inclinations never
change, but by some superior virtue. A loadstone will not
cease to draw iron, while that attractive quality remains in it.
The wolf can never love the lamb, nor the lamb the wolf; nothing
but must act suitably to its nature. Water cannot but moisten,
fire cannot but burn. So likewise the corrupt nature of man being
possessed with an invincible contrariety and enmity to God, will
never suffer him to comply with God. And the inclinations of a
sinner to sin being more strengthened by the frequency of sinful
acts, have as great a power over him, and as natural to him, as
any qualities are to natural agents: and being stronger than any
sympathies in the world, cannot by a man’s own power, or the power
of any other nature equal to it, be turned into a contrary channel.

(2.) Nothing can act beyond its own principle and nature.
Nothing in the world can raise itself to a higher rank of being
than that which nature has placed it in; a spark cannot make itself
a star, though it mount a little up to heaven; nor a plant endue
itself with sense, nor a beast adorn itself with reason; nor a
man make himself an angel. Thorns cannot bring forth grapes, nor
thistles produce figs because such fruits are above the nature
of those plants. So neither can our corrupt nature bring forth
grace, which is a fruit above it. Effectus non excedit virtutem
suae causae [the effect cannot exceed the power of its cause]:
grace is more excellent than nature, therefore cannot be the fruit
of nature. It is Christ’s conclusion, “How can you, being
evil, speak good things?” Matt. 12:33, 34. Not so much as
the buds and blossoms of words, much less the fruit of actions.
They can no more change their natures, than a viper can do away
with his poison. Now though this I have said be true, yet there
is nothing man does more affect in the world than a self-sufficiency,
and an independence from any other power but his own. This attitude
is as much riveted in his nature, as any other false principle
whatsoever. For man does derive it from his first parents, as
the prime legacy bequeathed to his nature: for it was the first
thing uncovered in man at his fall; he would be as God, independent
from him. Now God, to cross this principle, allows his elect,
like Lazarus, to lie in the grave till they stink, that there
may be no excuse to ascribe their resurrection to their own power.
If a putrefied rotten carcass should be brought to life, it could
never be thought that it inspired itself with that active principle.
God lets men run on so far in sin, that they do unman themselves,
that he may proclaim to all the world, that we are unable to do
anything of ourselves towards our recovery, without a superior
principle. The evidence of which will appear if we consider,

1. Man’s subjection under sin. He is “sold under sin,”
Rom. 7:14, and brought “into captivity to the law of sin,”
ver. 23. “Law of sin:” that sin seems to have a legal
authority over him; and man is not only a slave to one sin, but
many, Tit. 3:3, “serving divers lusts.” Now when a man
is sold under the power of a thousand lusts, every one of which
has an absolute tyranny over him, and rules him as a sovereign
by a law; when a man is thus bound by a thousand laws, a thousand
cords and fetters, and carried whither his lords please, against
the dictates of his own conscience and force of natural light;
can any man imagine that his own power can rescue him from the
strength of these masters that claim such a right to him, and
keep such a force upon him, and have so often baffled his own
strength, when he attempted to turn against them?

2. Man’s affection to them. He does not only serve them,
but he serves them, and every one of them, with delight and pleasure;
Tit. 3:3. They were all pleasures, as well as lusts; friends as
well as lords. Will any man leave his sensual delights and such
sins that please and flatter his flesh? Will a man ever endeavour
to run away from those lords which he serves with affection? having
as much delight in being bound a slave to these lusts, as the
devil has in binding him. Therefore when you see a man cast away
his pleasures, deprive himself of those comfortable things to
which his soul was once knit, and walk in paths contrary to corrupt
nature, you may search for the cause anywhere, rather than in
nature itself. No piece of dirty, muddy clay can form itself into
a neat and handsome vessel; no plain piece of timber can fit itself
for the building, much less a crooked one. Nor a man that is born
blind, give himself sight.

God deals with men in this case as he did with Abraham. He would
not give Isaac while Sarah’s womb, in a natural probability, might
have borne him; but when her womb was dead, and age had taken
away all natural strength of conception, then God gives him; that
it might appear that he was not a child of nature, but a child
of promise.