Thursday of Holy Week (Holy Thursday) Jesus Institutes the Eucharist and Holy Orders

"May we never boast of anything
except the cross of our Lord Jesus Christ:
He is our salvation, life, and resurrection;
through Him we have been saved and set free." (cf. Gal 6:14)
On Holy Thursday, in the morning, the Church celebrates the rite of the blessing of the holy oils during the Chrism Mass, and in the evening remembers the Last Supper of the Lord during the Evening Mass, in which Christ instituted the Eucharist and Holy Orders. This marks the beginning of the Easter Triduum.
On this day, we remember when Jesus shared His last seder meal with the twelve Apostles in the Upper Room, known as the Cenacle. Saint Paul, along with the evangelists Mark, Luke, and Matthew, recount the details of the Last Supper during which, taking bread and wine, Christ gave thanks and offered His Body and Blood for the salvation of humanity.
During this Supper, Jesus also humbled Himself to serve by washing the feet of His disciples. He made Himself their servant, saying:
“If I, therefore, the master and teacher, have washed your feet, you ought to wash one another’s feet. I have given you a model to follow, so that as I have done for you, you should also do.”
After the celebration of the Mass of the Lord’s Supper, the Blessed Sacrament is taken to the place of reposition. The altar is stripped bare, the cross is removed — all of it recalling the stripping of His vestments before being nailed to the cross. It is a time of Adoration, and the faithful remain in prayer before the Most Blessed Sacrament late into the night.
The hour of trial approaches — Christ goes to the olive garden of Gethsemane with the Apostles to keep watch and pray.