An evil disease - Margin, “a thing of Belial.” The Hebrew is literally “a word of Belial.” This has been very variously understood and interpreted. The Septuagint renders it: λόγον παράνομον logon paranomon - wicked word; “a wicked determination” (Thompson); that is, they formed a wicked purpose against him, to wit, by saying that he was now confined to his bed, and could not rise again. The Latin Vulgate renders it in a similar manner: Verbum iniquitum constituerunt adversum me. Luther: “They have formed a wicked device (Bubenstuck) against me;” they behave in a knavish or wicked manner. DeWette, “Destruction (Verderben) or punishnnent (Strafe) is poured upon him.” The term rendered “disease” means properly “word” or “thing;” and Prof. Alexander renders it, “A word of Belial is poured upon him.” The word rendered “evil, Belial,” means literally “without use” - בליעל belı̂ya‛al - from בלי belı̂y, “not or without,” and יעל ya‛al, “use or profit.”
Then it means worthlessness, wickedness, destruction; and hence, in connection with man, denotes one who is wicked, worthless, abandoned. It is difficult to determine its meaning here. The connection Psalms 41:3 would seem to suggest the idea adopted by our translators; the words themselves would seem rather to convey the idea of some reproach, or harsh saying - some vain, wicked, malicious words that were uttered against him. That there was disease in the case, and that the psalm was composed in view of it, and of the treatment which the author experienced from those who had been his professed friends when suffering under it, seems to me to be manifest from Psalms 41:1, Psalms 41:3-4, Psalms 41:8; but it is probable that the reference in this expression is not to the disease, but to the words or the conduct of his calumniators. It is evident from the pronoun him - the third person - that this refers, as our translators have indicated by the words they say to something that they said in regard to him; something which they affirmed as the result of their observations on his condition, Psalms 41:6-7. The true idea, therefore, I think is this: “They say - that is, those who came to see me said - A ‘word of evil’ - “a sentence of evil or destruction” - is poured upon him. He is suffering under such a ‘word of destruction;’ or, such a word (that is, sentence) as will involve his destruction, by way of punishment for his sins; therefore all is over with him, and he must die. He can hope to rise no more.” This would express the idea that they regarded his death as certain, for he seemed to be under a sentence which made that sure.
Cleaveth fast unto him - Or rather, “is poured upon him.” The word used here - צוּק tsûq - means:
(1) to be narrow, straitened, compressed; and then
(2) to pour out - as metal is poured out Job 28:2, or as words are poured out in prayer Isaiah 26:16.
Here it would seem to mean that such a sentence was poured upon him, or that he had become submerged or swallowed up under it. It was like the pouring out of a torrent on him, overwhelming him with floods of water, so that he could not hope to escape, or to rise again.
And now that he lieth, he shall rise up no more - There is no hope for him; no prospect that he will ever get up again. They felt that they might indulge their remarks, therefore, freely, as he would not be able to take revenge on them, and their expectations and hopes were about to be accomplished by his death. Compare Psalms 41:5. As a part of his sufferings, all this was aggravated by the fact that they regarded those sufferings as full proof of his guilt; that he could not reply to their accusations; and that be was about to die under that imputation.