'Knees' in the Bible

All hands shall be feeble, and all knees shall melt into water.

And it shall be, when they say unto thee, Wherefore dost thou sigh? that thou shalt say, Because of the tidings, for it cometh; and every heart shall melt, and all hands shall be feeble, and every spirit shall languish, and all knees shall melt into water: behold, it cometh; it is here, saith the Lord Jehovah.

And he measured a thousand cubits, and caused me to pass through the waters: the waters were to the knees. And he measured a thousand and caused me to pass through: the waters were to the loins.