His bones are full of the sin of his youth; literally, his bones are full of his youth; i.e. lusty and strong, full of youthful vigour. There is no sign of weakness or decay about them. Yet they shall lie down with him in the dust. A little while, and these vigorous bones, this entire body, so full of life and youth, shall be lying with the man himself, with all that constitutes his personality, in the dust of death (comp. Job 20:24, Job 20:25).
Though wickedness be sweet in his mouth; i.e. though the wicked man delight in his wickedness, and gloat over it, and keep the thought of it in his mind, as a gourmand keeps, so long as he can, a delicious taste in his mouth; though he, as it were, hide it under his tongue, in order not to let it escape him; though he spare it, and forsake it not; but keep it still within his mouth, yet, notwithstanding all this, disgust and nausea arrive in course of time (see the next two verses). It is, perhaps, the most surprising among the phenomena of wickedness that men can gloat over it, voluntarily recur to it, make a boast of it, recount signal instances of it to their friends, and seem to find a satisfaction in the recollection. One would have expected that shame and self-disapproval and fear of retribution would have led them to dismiss their wicked acts from their thoughts as soon as possible. But certainly the fact is otherwise.