In the liturgical year, Holy Thursday marks the beginning of the Sacred Triduum that stands as the high point of the entire liturgical year as the Triduum commemorates the Lord Jesus’ passion, death, and resurrection.
For it is in these mysteries that Christ accomplishes His redeeming work of freeing us from sin and gifting us with a share in His eternal kingdom. This “triduum” contains the three separated, but deeply connected moments of the Mass of the Lord’s Supper on Holy Thursday evening, the Celebration of the Passion of the Lord on Good Friday, and the Easter Vigil in the Holy Night after dark on Holy Saturday. In fact, these three moments are so intimately connected that they are kept as one liturgy (and hence this is why the Mass on Holy Thursday and the service on Good Friday do not conclude with a blessing or dismissal and why the service on Good Friday and the Easter Vigil Mass do not begin with a Sign of the Cross and greeting).