The Ten Commandments. Of all the ten, there is one that is unique. The other nine have a reasonable feel to them- worship God alone, don't murder, don't steal. But one stands out as unique and particular to the Hebrew God, and that is, "Remember that thou keep holy the sabbath day." Because God rested on that day:
Remember that thou keep holy the sabbath day. Six days shalt thou labour, and shalt do all thy works. But on the seventh day is the sabbath of the Lord thy God: thou shalt do no work on it, thou nor thy son, nor thy daughter, nor thy manservant, nor thy maidservant, nor thy beast, nor the stranger that is within thy gates. For in six days the Lord made heaven and earth, and the sea, and all things that are in them, and rested on the seventh day: therefore the Lord blessed the seventh day, and sanctified it. [Exodus 20:8-11]
Jesus Christ, the Second Person of the Holy Trinity, the Son of God- God from God, Light from Light- died on the cross just before the start of the Sabbath evening.
And about the ninth hour Jesus cried with a loud voice, saying: Eli, Eli, lamma sabacthani? that is, My God, my God, why hast thou forsaken me? And some that stood there and heard, said: This man calleth Elias. And immediately one of them running took a sponge, and filled it with vinegar; and put it on a reed, and gave him to drink. And the others said: Let be, let us see whether Elias will come to deliver him. And Jesus again crying with a loud voice, yielded up the ghost. [Matthew 27:46-50]
The ninth hour was about 3:00 in the afternoon. It would have been about 4:00 when Joseph of Arimathea asked Pilate for the body of Jesus.* There would have been time before sunset to lay His body in the tomb, and that is what we are meant to understand, that all this was done to avoid any work on the Sabbath.
*(Orchard, Bernard. A Catholic Commentary on Holy Scripture. London: Thomas Nelson, 1953. p. 903)
He rose on the morning of the day following the Sabbath. He was dead three days, but not 72 hours. He effectively spent the Sabbath in the tomb, dead.
And in the end of the sabbath, when it began to dawn towards the first day of the week, came Mary Magdalen and the other Mary, to see the sepulchre. And behold there was a great earthquake. For an angel of the Lord descended from heaven, and coming, rolled back the stone, and sat upon it. [Matthew 28:1-2]
What did Jesus do when He descended to the dead? Did He storm the gates of Hell to rescue souls? Did He wrestle with the devil? Would He have to do such a thing? No, His victory was on the cross. He descended already the Victor. He would not have had to fight demons. No, the nature of Jesus gives us the answer. He was the Life, and He was the Light. Life and Light entered death on the eve of the Passover Sabbath. His body rested in the tomb on the Sabbath. He rose again because it was His nature to rise. God cannot die. God, who cannot die in the Spirit, sent His Son who died in the Body, to enter death. In death, His presence illuminated that area that original sin had made dark. His presence, as Creator, having brought Light to that area that was dark, brought it to Himself. As His touch could heal, so His presence in death could overcome it. When He rose, following the Sabbath, the battle for souls was over. Anyone willing to follow Christ could share in His victory. His own would know Him. As His touch could heal, so His presence could overcome death.
Following is an "Ancient homily" of Bishop Melito of Sardis in the Second Century, said on Holy Saturday in the Liturgy of the Hours. (from https://www.catholic.org/lent/story.php?id=41152)
"The whole earth keeps silence because the King is asleep´Something strange is happening - there is a great silence on earth today, a great silence and stillness. The whole earth keeps silence because the King is asleep. The earth trembled and is still because God has fallen asleep in the flesh and he has raised up all who have slept ever since the world began. God has died in the flesh and hell trembles with fear.
He has gone to search for our first parent, as for a lost sheep. Greatly desiring to visit those who live in darkness and in the shadow of death, he has gone to free from sorrow the captives Adam and Eve, he who is both God and the son of Eve. The Lord approached them bearing the cross, the weapon that had won him the victory.
At the sight of him Adam, the first man he had created, struck his breast in terror and cried out to everyone: "My Lord be with you all." Christ answered him: "And with your spirit." He took him by the hand and raised him up, saying: "Awake, O sleeper, and rise from the dead, and Christ will give you light."
"I am your God, who for your sake have become your son. Out of love for you and for your descendants I now by my own authority command all who are held in bondage to come forth, all who are in darkness to be enlightened, all who are sleeping to arise. I order you, O sleeper, to awake. I did not create you to be held a prisoner in hell.
"Rise from the dead, for I am the life of the dead. Rise up, work of my hands, you who were created in my image. Rise, let us leave this place, for you are in me and I am in you; together we form only one person and we cannot be separated.
"For your sake I, your God, became your son; I, the Lord, took the form of a slave; I, whose home is above the heavens, descended to the earth and beneath the earth. For your sake, for the sake of man, I became like a man without help, free among the dead. For the sake of you, who left a garden, I was betrayed to in a garden, and I was crucified in a garden.
'See on my face the spittle I received in order to restore to you the life I once breathed into you. See there the marks of the blows I received in order to refashion your warped nature in my image. On my back see the marks of the scourging I endured to remove the burden of sin that weighs upon your back. See my hands, nailed firmly to a tree, for you who once wickedly stretched out your hand to a tree.
"I slept on the cross and a sword pierced my side for you who slept in paradise and brought forth Eve from your side. My side has healed the pain in yours. My sleep will rouse you from your sleep in hell. The sword that pierced me has sheathed the sword that was turned against you.
'Rise, let us leave this place. The enemy led you out of the earthly paradise. I will not restore you to that paradise, but I will enthrone you in heaven. I forbade you the tree that was only a symbol of life, but see, I who am life itself am now one with you. I appointed cherubim to guard you as slaves are guarded, but now I make them worship you as God.
"The throne formed by cherubim awaits you, its bearers swift and eager. The bridal chamber is adorned, the banquet is ready, the eternal dwelling places are prepared, the treasure houses of all good things lie open. The kingdom of heaven has been prepared for you from all eternity".