The following day, Thursday, Nisan 15, was the combined Feast of Passover, and the first day of the Feast of Unleavened Bread. It was a Yom Tov, a High Holy Day, a special Sabbath, for that Sabbath was a high day. John 19.31
Jesus was now in the grave, and the special Sabbath had begun:
On the next day,(Nisan 15) after the Day of Preparation, the Chief Priests and Pharisees gathered to Pilate, saying, ‘We remember, while He was still alive, how that deceiver said, ‘After three days I will rise.’ Therefore command that the tomb be made secure until the third day, lest His disciples come by night and steal Him away, and say, ‘He has risen from the dead.’ So the last deception will be worse than the first.’
Pilate said, ‘You have a (Temple) guard; make it secure.’ So they made the tomb secure, sealing the stone and setting the (Temple) guard (of Levites). Matthew 27.62-66
As Jesus Himself prophesied:
For as Jonah was three days and three nights in the belly of the great fish, so will the Son of Man be three days and three nights in the heart of the earth. Matthew 12.40
After the hurried burial the women returned (to Bethany) and prepared spices and fragrant oils, and they rested on the (special) Sabbath, Nisan 15, which ended at sunset on Thursday evening at about 6pm.
His grave was guarded to prevent anyone approaching it to steal Him away for three days, so the women were prevented by the guards from going to the tomb on Nisan 16, Friday. At sunset on Friday, Nisan 16, the normal weekly Sabbath began, Nisan 17, and so they were again unable to go to the tomb again.
Very early in the morning, on the first day of the week, (Sunday Nisan 18), they came to the tomb when the sun had risen. There was a great earthquake; for an angel of the Lord...came and rolled back the stone...and said to the women, ‘I know that you seek Jesus. He is not here; for He is risen’…
Mark 16.2, Matthew 28.2-6
It was the same earthquake that Matthew had reported earlier. Not only was Jesus resurrected, but:
The earth quaked, rocks were split, graves were opened; and many bodies of the saints who had fallen asleep were raised; coming out of the graves after His resurrection, they appeared to many. Matthew 27.51-53
The angel said, He is not here, because Jesus had already risen. In fulfillment of His prophecy about Jonah, He had risen just before sunset the previous evening, about an hour before the end of the Sabbath, Nisan 17, exactly three days and three nights since He had been buried about an hour before sunset on the Day of Preparation, Nisan 14.
Because He had been in the grave He was unclean for seven days according to Numbers 19:
Who touches a dead body shall be unclean seven days. He shall purify himself... on the third and seventh day; then he will be clean….
This was why He said to Mary, Do not touch me. The first person to touch Him was Thomas, because, after eight days, He was clean:
After eight days His disciples were again inside, and Thomas with them. ... Jesus said to him, ‘Reach your hand here, and put it into My side.’
The events of Passion Week changed the world. As we have seen, Jesus fulfilled the prophecies in the Old Testament that proved who He was, and that only He had the authority to redeem us. In conclusion, when we are sharing our Passover Seder and:
When our children say to us, ‘What do you mean by this service?’, we shall say, ‘It is the Passover sacrifice of the LORD’ because Messiah, our Passover, was sacrificed for us.
Therefore let us keep the Feast of Passover together, being one new man from the two, Jew and Gentile, having made peace, and through Him been reconciled to God in one body.
Exodus 12.26-27, 1 Corinthians 5.7-8, Ephesians 2.15-16.
These things are written that you may believe that Jesus is the Messiah, the Son of God, and that believing you may have Life in His Name. John 20.31