The week following the Sunday of St Mary of Egypt is called Palm or Branch Week. At the Tuesday services of this week the Church recalls that Jesus’ friend Lazarus has died and that the Lord is going to raise him from the dead (Jn 11). As the days continue toward Saturday, the Church, in its hymns and verses, continues to follow Christ towards Bethany to the tomb of Lazarus. On Friday evening, the eve of the celebration of the Resurrection of Lazarus, the “great and saving forty days” of Great Lent are formally brought to an end:

Having accomplished the forty days for the benefit of our souls, we pray to Thee, O Lover of Man, that we may see the holy week of Thy passion, that in it we may glorify Thy greatness and Thine unspeakable plan of salvation for our sake. ...(Vesper Hymn)

Lazarus Saturday is a paschal celebration. It is the only time in the entire Church Year that the resurrectional service of Sunday is celebrated on another day. At the liturgy of Lazarus Saturday, the Church glorifies Christ as “the Resurrection and the Life” who, by raising Lazarus, has confirmed the universal resurrection of mankind even before his own suffering and death.

By raising Lazarus from the dead before Thy passion, Thou didst confirm the universal resurrection, O Christ God! Like the children with the branches of victory, we cry out to Thee, O Vanquisher of Death: Hosanna in the highest! Blessed is he that comes in the name of the Lord! (Troparion).

Christ —the Joy, the Truth and the Light of All, the Life of the world and its Resurrection—has appeared in his goodness to those on earth. He has become the Image of our Resurrection, granting divine forgiveness to all (Kontakion).

At the Divine Liturgy of Lazarus Saturday the baptismal verse from Galatians: As many as have been baptizedl into Christ have put on Christ (Gal 3:27) replaces the Thrice-holy Hymn thus indicating the resurrectional character of the celebration, and the fact that Lazarus Saturday was once among the few great baptismal days in the Orthodox Church Year. Because of the resurrection of Lazarus from the dead, Christ was hailed by the masses as the long-expected Messiah-King of Israel. Thus, in fulfillment of the prophecies of the Old Testament, he entered Jenrsalem, the City of the King, riding on the colt of an ass (Zech 9:9; Jn 12:12). The crowds greeted him with brancfies in their hands and called out to him with shouts of praise: Hosanna! Blessed is he who comes in the name of the Lord! The Son of David! The King of Israel! Because of this glorification by the people, the priests and scribes were finally driven “to destroy him, to put him to death” (Lk 19:47; Jn 11:53, 12:10).

Source:  www.oca.org