John Calvin Commentary Psalms 41:8

"An evil disease, [say they], cleaveth fast unto him; And now that he lieth he shall rise up no more." — Psalms 41:8 (ASV)

An evil deed of Belial cleaved fast to him. From this verse it appears that they had conspired in this way for his destruction, because they regarded him as a wicked man, and a person worthy of a thousand deaths. The insolence and arrogance which they showed towards him came from the false and wicked judgment they had formed about him, and which he mentioned in the beginning of the psalm.

They say, therefore, that an evil deed of Belial holds him shut up, and, as it were, bound fast. This the verb יצוק, yatsuk, properly means; but in translating the verse I have followed the most commonly accepted translation, reading cleaveth fast to him, etc. This expression is by others rendered spreadeth upon him, but this interpretation seems to me to be too forced.

Regarding the word Belial, we have already spoken of it in Psalm 18. But as grammarians maintain that it is compounded of בלי, beli, and יעל, yaäl, which mean not to rise, the expression, thing of Belial, (for that is its literal meaning in Hebrew,) I understand in this place as meaning an extraordinary and hateful crime, which, as is commonly said, can never be expiated, and from which there is no possibility of escape; unless, perhaps, some would prefer to relate it to the affliction itself under which he suffered, as if his enemies had said that he was seized by some incurable disease.

However this may be, his enemies regarded it as absolutely certain that God was completely hostile to him, and would never be reconciled to him, since He was chastising him so severely. When they add in the following clause, he shall never be able to rise again, this clearly shows that they completely cut off all his hope of recovery.

And certainly it was a severe temptation to David, who had the testimony of a good conscience within himself, to think that he was regarded by people as someone pursued by God's vengeance; indeed, that they even cast him headlong into hell.

But it pleased God to test His servant in this way, so that, trusting the testimony of his own conscience, he should pay no attention to what people might say, or be troubled by the reproaches they might cast upon him. It was also God's design to teach us, by his example, that we must seek the reward of our righteousness somewhere other than in this world, since we see by what unequal standards the world often estimates the difference between virtue and vice.