The Resurrection of Christ is the central event of all Sacred history. Easter is one of the main Christian Holidays. On this day, believers remember the most important event - the resurrection of Jesus Christ from the dead, who was crucified on the cross for the sins of all mankind. The bright Resurrection of Christ is called Easter (Passover), because the events of Holy Week - the betrayal of Judah, the capture of Christ, his trial and crucifixion - occurred on the eve of Jewish Passover, and the Resurrection of Christ - on the night of Easter.
In its turn, the Hebrew word "Passover" or "Pesah" is translated as "pass by", "deliverance". The Jewish Passover is dedicated to the deliverance of the Jews from Egypt and their liberation from Egyptian slavery. In the Christian Church, the word "Pesah" received a special meaning and means the transition from death to eternal life with Christ.
This is the oldest holiday which was celebrated in the Apostolic times and since those ancient times the church serves Easter Liturgy at night. Exactly as the Jews who were awake on the night of deliverance from Egyptian slavery, Christians are awake on the Holy night of Easter.