The Holy Saturday is the greatest day of the sepulchral rest. The day before, on the sixth day of the week, the new Adam died on the cross. Just as the first Adam was created on the sixth day, so all mankind was created by the new Adam, by Christ's death on the cross. On the seventh day, God and so Christ rested in the grave - in His body. His soul, on the other hand, was very active. He went down into the underworld, as we confess in the Creed: "He descended into the kingdom of death".
This kingdom of death is also called Hades, Sheol or Hell in the New Testament. Until the coming of Christ, all the deceased were in the realm of the underworld, sleeping in that Sheol and waiting for the Redeemer. But as we know from the parable of the rich man and the poor Lazarus, there was a difference: the damned were already in the final separation from God and the righteous were asleep in Sheol, in the realm of death.
But the great suffering in the kingdom of death is that in death one is deprived from the vision of God. There was a mystic in the last century, Adrienne von Speyer, who said that on Holy Saturday, Christ himself experienced the last consequence of death in his soul, namely hell. Christ can of course not be damned by God, because he is God himself. And yet he experienced the torments that sin entails in his human soul, so that he would also experience this last agony of man and to pull us out of it. The church fathers say: "The Lord descends into the kingdom of death as a victor because he defeated the devil on the cross - the devil is the master of death. Christ goes to the fallen asleep righteous Adam and Eve and to all who had lived until then. He fetches them and delivers them from the realm of death.
For the last 150 years or so, there have been currents in theology that claim that there is no hell or that in the end everyone will be saved — a doctrine which the Church has always condemned, that is, since the time of Origen. God gives us more and more mystics who experienced hell and they tell and warn us about it. Life is given to us in order to turn to Jesus and to let ourselves be saved by him, and to direct our lives towards him. Holy Saturday is therefore a day to stay with the Mother of God in the silence of the sepulchre and to thank the Lord that he descended into hell to free us from the kingdom of death. ∎