'Corner stones' in the Bible

That our sons may be as plants grown up in their youth; that our daughters may be as corner stones, polished after the similitude of a palace:

The princes of Zoan are become foolish, the princes of Noph are deceived; and the corner-stones of its tribes have caused Egypt to err.

so that neither cornerstones, nor pinnacles, nor foundation stones shall be taken any more out of thee, but waste and desolate shalt thou lie for evermore, sayeth the LORD.