From Protopresbyter Alexander Schmemann: Great and Holy Saturday:
Holy Saturday is a neglected day in parish life. Few people attend the Services. Popular piety usually reduces Holy Week to one day — Holy Friday. This day is quickly replaced by another — Easter Sunday. Christ is dead and then suddenly alive. Great sorrow is suddenly replaced by great joy. In such a scheme Holy Saturday is lost.
In the understanding of the Church, sorrow is not replaced by joy; it is transformed into joy. This distinction indicates that it is precisely within death the Christ continues to effect triumph.
TRAMPLING DOWN DEATH BY DEATH
We sing that Christ is ". . . trampling down death by death" in the troparion of Easter. This phrase gives great meaning to Holy Saturday. Christ’s repose in the tomb is an "active" repose. He comes in search of His fallen friend, Adam, who represents all men. Not finding him on earth, He descends to the realm of death, known as Hades in the Old Testament. There He finds him and brings him life once again. This is the victory: the dead are given life. The tomb is no longer a forsaken, lifeless place. By His death Christ tramples down death.