The Archdiocese of Milwaukee encouraged the faithful to join the church in prayer through the Triduum, which began Thursday evening and concludes on the evening of Easter.

Though chronologically three days, the Triduum liturgically is one day, the archdiocese explained on Facebook. “That is why there is no closing song on Holy Thursday or an opening or closing song on Good Friday. Throughout the Triduum, please join us in prayer.”

The Triduum begins on the evening of Holy Thursday, after the Last Supper, according to the U.S. Conference of Catholic Bishops (USCCB).

That day carries significance because it is when Jesus instituted the Sacrament of the Eucharist, offering his body and blood to his disciples in the form of bread and wine, the USCCB said. It is also the day that Jesus instituted the priesthood, entrusting the legacy of the church to his apostles.

The Gospel reading for Easter Mass this Sunday comes from the book of John, chapter 20, the USCCB stated.

The selected reading describes Mary Magdalene’s return to the tomb where Jesus had been buried. When she gets there, she notices that the stone blocking the entrance had been rolled aside, according to the USCCB website. Mary runs to alert two of Jesus' disciples, who returned to the tomb with her. Simon and Peter went inside and found Jesus' burial cloths. The disciples did not yet understand that Jesus had risen from the dead.

Easter celebrates Jesus' Resurrection, which confirmed that he was the true son of God and signaled to all who believe in him, that they would be granted eternal life in Heaven, according to Christianity.com. The Resurrection is the cornerstone of the Christian faith.