The Paschal Triduum begins with the Evening Mass In Cena Domini on Holy Thursday, continues through the Friday of the Lord's Passion, reaches its summit in the Solemn Paschal Vigil, and comes to a close with Sunday Vespers of the Lord's Resurrection - a full three days - evening Thursday through evening Sunday (According to the General Norms for the Liturgical Year and the Calendar).
… For Christ knew our hunger for Himself.
"Without the priest, the passion and death
of our Lord would be of no avail.
It is the priest who continues the work
and they will end by worshiping the beasts there...
St John Vianney
Patron of all priests
They rely on our prayers - and we rely on our priests!
and tomorrow and everyday...
(St Charles Borremeo)