The day that Jesus was buried on and the day of His resurrection also have significance because of two other feast days that God ordained the Jews to keep immediately following the Passover.
In the Book of Leviticus, God gave to the Jews the dates of the seven feasts that He would require them to keep. Passover was to occur on the 14th of Nisan which was the day that Jesus was crucified. On the 15th of Nisan, the Jews were to observe the week-long feast of Unleavened Bread. They were to eat bread that contained no leaven in it. The Bible records that leaven represents sin in a spiritual sense: "Your glorying is not good. Know you not that a little leaven leavens the whole lump? Purge out therefore the old leaven that you may be a new lump, as ye are unleavened. For even Christ our Passover is sacrificed for us: Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth." (1 Corinthians 5:6-8) Jesus had taken the world's sins upon Himself and died. He was buried, and our sins with Him, on the 15th of Nisan, 33 A.D. In doing so Jesus fulfilled the second of the seven Jewish feasts.