'Knees' in the Bible

Then Solomon, after making all these prayers and requests for grace to the Lord, got up from his knees before the altar of the Lord, where his hands had been stretched out in prayer to heaven;

So Ahab went up to have food and drink, while Elijah went up to the top of Carmel; and he went down on the earth, putting his face between his knees.

But I will keep safe seven thousand in Israel, all those whose knees have not been bent to Baal, and whose mouths have given him no kisses.