(Hebrew יצחק) A symbolic character in Genesis by Moses. Isaac is the son of Sarah and Abraham (Chesed), and represents the outcome of sexual transmutation, the entrance into initiation. Thus, Isaac is generally related to the sephirah Geburah.
"And Elohim said, Sarah thy wife shall bear thee a son indeed; and thou shalt call his name יצחק Isaac: and I will establish my covenant with him for an everlasting covenant, and with his seed after him." - Genesis 17:19