'Knee' in the Bible

And when they had platted a crown of thorns, they put it upon his head, and a reed in his right hand: and they bowed the knee before him, and mocked him, saying, Hail, King of the Jews!

But what saith the answer of God unto him? I have reserved to myself seven thousand men, who have not bowed the knee to the image of Baal.

For it is written, As I live, saith the Lord, every knee shall bow to me, and every tongue shall confess to God.

That at the name of Jesus every knee should bow, of things in heaven, and things in earth, and things under the earth;