| Clarke's Commentary on the Bible All knees shall be weak as water - Calmet understands this curiously: La frayeur dont on sera saisi, fera qu'on ne pourra retenir son urine. D'autres l'expliquent d'une autre souillure plus honteuse. I believe him to be nearly about right. St. Jerome is exactly the same: Pavoris magnitudine, urina polluet genua, nec valebit profluentes aquas vesica prohibere. This and other malretentions are often the natural effect of extreme fear or terror.
Gill's Exposition of the Entire BibleAll hands shall be feeble,.... No strength in them, to lay hold on weapons of war to defend themselves, or fight the enemy; no heart nor courage in them, to go forth and meet him; and even afraid to lift up their voice in mourning, lest they should be heard, and pursued, and taken: and all knees shall be weak as water; tremble and beat one against another, for fear of the enemy; or, "shall flow with water,'' as the Targum; either with sweat or urine, which are sometimes both caused by fear.
Geneva Study BibleAll hands shall be feeble, and all knees shall be weak as water.
King James Translators' Notesbe weak...: Heb. go into water
Jamieson-Fausset-Brown Bible Commentary17. shall be weak as water-literally, "shall go (as) waters"; incapable of resistance (Jos 7:5; Ps 22:14; Isa 13:7).
Matthew Henry's Concise Commentary7:16-22 Sooner or later, sin will cause sorrow; and those who will not repent of their sin, may justly be left to pine away in it. There are many whose wealth is their snare and ruin; and the gaining the world is the losing of their souls. Riches profit not in the day of wrath. The wealth of this world has not that in it which will answer the desires of the soul, or be any satisfaction to it in a day of distress. God's temple shall stand them in no stead. Those are unworthy to be honoured with the form of godliness, who will not be governed by its power. | 
