Bede : It was evening, and it was morning, the fourth day. This is that memorable evening in which the people of God in Egypt offered a lamb in celebration of Passover; this morning, which first saw the yoke of long servitude being cast off and the journey of freedom beginning. It is written, the Lord said to Moses: This month shall be for you the beginning of months; it shall be the first month of the year for you. On the tenth day of this month, each man shall take a lamb for the families and households, and you shall keep it until the fourteenth day of the month, and the whole assembly of the congregation of Israel shall kill it at twilight (Exodus 12:2), etc. On that same evening, to complete the legal sacraments of Passover, our Lord initiated the celebration of the mysteries of His body and blood after eating the lamb typologically; at that dawning morning, as an unblemished lamb, redeeming us by His blood, He freed us from the servitude of demonic domination. The day of that full moon, which proceeded on the fourth day in the creation of the world, in the time of the Lord's passion, by the grace of a higher sacrament, fell on the fifth day of Sabbath, so that the Lord was crucified on the sixth day of Sabbath, rested in the tomb on the Sabbath itself, and by His resurrection consecrated the first day of Sabbath, granting us also in it the faith and hope of rising from the dead and entering into eternal light. — Commentary on Genesis (Hexaemeron)