Jesus and His Apostles celebrated the Passover, according to the Law, on the evening (or beginning) of the 14th. of Nissan. While Israel was in slavery in Egypt, God commanded the Jews to roast and eat a young lamb. The lamb’s blood was to be brushed on the top and sides of the frame around the outside door. Then angel of death passed over the marked Jewish homes, but killed all the first born in unmarked homes, both of men and domestic animals, in all the rest of Egypt. The slaying of the lamb was a type of Jesus’s sacrifice

Returning to Jesus’s day, after Jesus celebrated the Passover, He instituted a memorial of His sacrificial death. (Today, some churches call the memorial, communion.) The Jewish day begins at sundown and ends the following sundown. Thus, Jesus could both partake of the passover lamb (symbolizing Himself) and fulfill the type as the actual passover lamb on the same day of Nissan 14. Jesus was crucified and buried on Friday afternoon of Nissan 14

John19:31 (NIV), “Now it was the day of Preparation (Friday, Nissan 14), and the next day (beginning after sunset on Friday, Nissan 15th.) was to be a special Sabbath. Because the Jewish leaders did not want the bodies left on the crosses during the Sabbath (Friday night Nissan 15), they asked Pilate to have the legs broken and the bodies taken down.” However, Jesus had already died and his legs were not broken.

Jesus was resurrected early Sunday morning (Nissan 17th.). Matthew 28:1-2, 5-6 (NIV), 1 “After the Sabbath, at dawn on the first day of the week, Mary Magdalene and the other Mary went to look at the tomb. 2 There was a violent earthquake, for an angel of the Lord came down from heaven and, going to the tomb, rolled back the stone and sat on it. … 5 The angel said to the women, ‘Do not be afraid, for I know that you are looking for Jesus, who was crucified. 6 He is not here; he has risen, just as he said. Come and see the place where he lay.’ ”

Jesus never instructed His followers to celebrate His resurrection; however, He did establish the memorial of His death to replace the yearly Passover type. 1 Corinthians 5:7-8 (CSB), “…For Christ our Passover lamb has been sacrificed. Therefore, let us observe the feast, not with old leaven or with the leaven of malice and evil, but with the unleavened bread of sincerity and truth.”