His bones are full of the sin of his youth - The words "of the sin" in our common translation are supplied by the translators. Gesenius and Noyes suppose that the Hebrew means, "His bones are full of youth;" that is, full of vigor and strength, and the idea according to this would be, that he would be cut off in the fulness of his strength. Dr. Good renders it forcibly,
"His secret lusts shall follow his bones,
Yea, they shall press upon him in the dust."
The Vulgate renders it, "His bones are full of the sins of his youth." The Septuagint, "His bones are full of his youth." The Chaldee Paraphrase, "His bones are full of his strength." The Hebrew literally is, "His bones are full of his secret things" (עלוּמו ‛âlûmāŷ) - referring, as I suppose, to the "secret, long-cherished" faults of his life; the corrupt propensities and desires of his soul which had been seated in his very nature, and which would adhere to him, leaving a withering influence on his whole system in advancing years. The effect is that which is so often seen, when vices corrupt the very physical frame, and where the results are seen long in future life. The effect would be seen in the diseases which they engendered in his system, and in the certainty with which they would bring him down to the grave. The Syriac renders it, "marrow," as if the idea were that he would die full of vigor and strength. But the sense is rather that his secret lusts would work his certain ruin.
Which shall lie down with him - That is, the results of his secret sins shall lie down with him in the grave. He will never get rid of them. He has so long indulged in his sins; they have so thoroughly pervaded his nature, and he so delights to cherish them, that they will attend him to the tomb. There is truth in this representation. Wicked people often indulge in secret sin so long that it seems to pervade the whole system. Nothing will remove it; and it lives and acts until the body is committed to the dust, and the soul sinks ruined into hell.

His bones are full of the sin of his youth - Our translators have followed the Vulgate, Ossa ejus implebuntur vitiis adolescentiae ejus; "his bones shall be filled with the sins of his youth." The Syriac and Arabic have, his bones are full of marrow; and the Targum is to the same sense. At first view it might appear that Zophar refers to those infirmities in old age, which are the consequences of youthful vices and irregularities. עלומו alumau, which we translate his youth, may be rendered his hidden things; as if he had said, his secret vices bring down his strength to the dust. For this rendering Rosenmuller contends, and several other German critics. Mr. Good contends for the same.

His bones are full [of the sin] of his youth, which (e) shall lie down with him in the dust.
(e) Meaning that he will carry nothing away with him but his sin.

His bones are full of the sins of his youth,.... Man is born in sin, and is a transgressor from the womb; and the youthful age is addicted to many sins, as pride, passion, lust, luxury, intemperance, and uncleanness; and these are sometimes brought to mind, and men are convinced of them, and corrected for them, when more advanced in years; and if not stopped in them, and reformed from them, they are continued in an old age; and the effects of them are seen in bodily diseases, which a debauched life brings upon them, not only to the rottenness and consumption of their flesh, but to the putrefaction of their bones; though this may be understood of the whole body, the bones, the principal and stronger parts, being put for the whole, and denote that general decay and waste which gluttony, drunkenness, and uncleanness, bring into, see Proverbs 5:11; Some interpret this of "secret" sins (p), as the word is thought to signify, which, if not cleansed from and pardoned, will be found and charged on them, and be brought into judgment, and they punished for them, Psalm 90:8;
which shall lie down with him in the dust: to be in the dust is to be in the state of the dead, to lie in the grave, where men lie down and sleep as on a bed; and this is common to good and bad men, all sleep in the dust of the earth, but with this difference, the sins of wicked men lie down with them; as they live in sin, they die in their sins; not that their sins die with them, and are no more, but they continue on them, and with them, and will rise with them, and will follow them to judgment, and remain with them after, and the guilt and remorse of which will be always on their consciences, and is that worm that never dies: of such it is said, that they "are gone down to hell with their weapons of war"; with the same enmity against God, against Christ, and his people, and all that is good, they had in their lifetime: and "they have laid their swords under their heads"; in the grave, and shall rise with the same revengeful spirit they ever had against the saints, see Revelation 20:8; "but their iniquities shall be upon their bones"; both them, and the punishment of them, Ezekiel 32:27. The Jewish commentator last mentioned interprets the whole verse of Balaam, who died at the age of thirty three, and whose prosperity died with him, he leaving nothing to his children; and so he interprets the following verses of the curse he was forced to hide, which he would gladly have pronounced, and of the riches he received from Balak falling into the hands of the Israelites.
(p) "ejus occultis", Montanus, Vatablus, Schmidt.

(Psalm 25:7), so Vulgate. GESENIUS has "full of youth"; namely, in the fulness of his youthful strength he shall be laid in the dust. But "bones" plainly alludes to Job's disease, probably to Job's own words (Job 19:20). UMBREIT translates, "full of his secret sins," as in Psalm 90:8; his secret guilt in his time of seeming righteousness, like secret poison, at last lays him in the dust. The English Version is best. Zophar alludes to Job's own words (Job 17:16).
with him--His sin had so pervaded his nature that it accompanies him to the grave: for eternity the sinner cannot get rid of it (Revelation 22:11).

Bones - His whole body, even the strongest parts of it. The sin - Of the punishment of it.