'Knees' in the Bible

All hands will be feeble and all knees without strength, like water.

And when they say to you, Why are you making sounds of grief? then say, Because of the news, for it is coming: and every heart will become soft, and all hands will be feeble, and every spirit will be burning low, and all knees will be turned to water: see, it is coming and it will be done, says the Lord.

And again, measuring a thousand cubits, he made me go through the waters which came up to my knees. Again, measuring a thousand, he made me go through the waters up to the middle of my body.