Zeuxis died laughing at the picture of an old woman When Satan has sucked out all the marrow

(Thomas Brooks, "Apples of Gold" 1660)

God usually begins with such early in life--whom He has
had thoughts of love and mercy towards, from everlasting.

If, in the spring and morning of your days, you do not bring
forth fruit to God--it is a hundred to one that you never shall
bring forth fruit to God when the days of old age shall overtake
you. It is rare, very rare--that God sows and reaps in old age.
Usually God sows the seed of grace in youth--which yields
the harvest of joy in old age.

Though true repentance is never too late--yet late
repentance is seldom true. Millions are now in hell, who
have flattered themselves with the thought of repenting
in old age! Yes, what can be more just and equal, that such
should seek and not find--who might have found when young,
but would not seek; and that God should shut His ears against
their late prayers--who have stopped their ears against His
early calls?

The ancient warriors would not accept an old man into their
army, as being unfit for service; and do you think that God
will accept of your dry bones--when Satan has sucked
out all the marrow? What king will take into his service
--those who have served his enemies all their days? And
will God? will God?

The Circassians, a kind of mongrel Christians, are said to
divide their life between sin and devotion--dedicating their
youth to rapine, and their old age to repentance. If this is
your case, I would not be in your case for ten thousand worlds!

"But since you rejected Me when I called, and no one gave
 heed when I stretched out My hand, since you ignored all
 My advice and would not accept My rebuke--I in turn will
 laugh at your disaster; I will mock when calamity overtakes
 you--when calamity overtakes you like a storm, when disaster
 sweeps over you like a whirlwind, when distress and trouble
 overwhelm you. Then they will call to Me but I will not answer;
 they will look for Me but will not find Me. Since they hated
 knowledge and did not choose to fear the Lord, since they
 would not accept My advice and spurned My rebuke--they
 will eat the fruit of their ways and be filled with the fruit
 of their schemes." Proverbs 1:24-31