'Knees' in the Bible

All of the hands will hang limp, and all of {the knees will be wet with urine}.

{And then} when they say to you, 'On account of what [are] you groaning?' then you must say, 'On account of [the] report, for it [is] coming, and every heart will be weak and all hands will hang limp and every spirit will be disheartened, and all knees will go [like] water.' Look! It [is] coming, and it will happen!" {declares} the Lord Yahweh.