The Jewish Pasch was celebrated annually at the command of God to commemorate the deliverance of the Jews from the bondage of Egypt - a deliverance granted on condition that the night before they were set free a lamb or kid without spot or blemish and the bones of which were preserved unbroken, be sacrificed and the blood sprinkled on the doorposts of every Hebrew house.
In the mind of God, this deliverance 'of the Jewish people from the bondage of Egypt with the attendant details was a foreshadowing of the Christian Pasch or Passover, when through the sacrifice of the Immaculate Lamb of God and the subsequent application of the merits of His blood to our souls through the Sacraments, we were set free from the bondage of sin and Satan.
So true is this, that in the early Church we find the term "pascha," applied equally to Good Friday and Easter Sunday.
Good Friday was styled the "Pasch of the Crucifixion," and Easter Sunday, the "Pasch of the Resurrection."
New Catholic Dictionary