A very good man named Simeon was told by God that he would not die until he had seen the Savior.  It was 40 days after Jesus’ birth when the Virgin Mary presented the baby Jesus at the Temple to Simeon, who was then over 150 years old.  God kept His promise to Simeon.  Just as the Virgin Mary did with Jesus, we still present each baby to the Church on the 40^th day after birth.