The synoptic Gospels state that Jesus celebrate the Passover on Thursday night (Passover fell on Friday), and in the Gospel of John the Friday is “the day of preparation”. This is because there were two groups of Jews with different practices: Pharisees and Sadducees. The Sadducees, moved the Passover to Saturday, and celebrated the day of preparation on Friday, rather than on Thursday as Jesus and the apostles did. Jesus kept the Passover strictly in accord with Moses Exodus 12 as did the Pharisees. (See the
The Navarre Study Bible - Gospel of Mark.)
Sunday is the Eighth Day of the Resurrection, and the times we live in are also the Eight Day.
No Mass on Good Friday:
The omission of the Mass proper marks in the mind of the Church the deep sorrow with which she keeps the anniversary of the Sacrifice of Calvary. Good Friday is a feast of grief. A black fast, black vestments, a denuded altar, the slow and solemn chanting of the sufferings of Christ, prayers for all those for whom He died, the unveiling and reverencing of the Crucifix, these take the place of the usual festal liturgy; while the lights in the chapel of repose and the Mass of the Presanctified is followed by the recital of vespers, and the removal of the linen cloth from the altar (“Vespers are recited without chant and the altar is denuded”).
Gilmartin, Thomas. “Good Friday.” The Catholic Encyclopedia. Vol. 6. New York: Robert Appleton Company, 1909.
newadvent.org/cathen/06643a.htm