Sacrifice

But his [Christ’s] sanctification did not consist in his becoming holy, since as God he was already holy. Rather according to the sense of how the term is used in the Old Testament, “That which is brought by any one to God by way of an offering or gifts, as sacred to him, is said to be sanctified according to the custom of the Law.” [Cyril of Alexandria] Sacrifices were set apart, offered and dedicated as holy to God. Therefore when Christ says he sanctifies himself for us, he means according to Cyril that, “he brought himself as a Victim and holy Sacrifice to God the Father, ‘reconciling the world unto himself’ and bringing the human race that has fallen away back into a relationship with God.” This reunion occurs through communion in the Spirit and sanctification because the Spirit is the one who knits us together and unites us with God.— Theosis, Volume 2, pages 152-153