Three days: they make all the difference
They are the three most important days on our Catholic calendar, but they are not holy days of obligation. They are, though, holy days. Commonly referred to as the Triduum, it is better if the words Sacred Paschal precede it, so these three days are the Sacred Paschal Triduum.
In a very real sense, the days are one continual celebration of the one Paschal Mystery.
Thursday of the Lord's Supper
The three readings of this Mass direct us toward the remaining days of the Triduum. Exodus recalls the instructions God gave Moses about the preparations for the Passover of the Jewish people, from slavery in Egypt to freedom in the Promised Land. From Paul's First Letter to the Corinthians, we hear how the Eucharist should be celebrated in that early church. This account is the first testimony to the "Last Supper," written around the year 50. The other meaning of the Eucharist is narrated for us with John's Gospel account of that same Supper and its Washing of the Feet.
As we celebrate this Eucharist (and truly, each Eucharist), we passover in the Exodus from slavery to sin to freedom in grace; we "proclaim the death of the Lord until he comes again" and we commit ourselves to humble service.
Friday of the Lord's Passion
The Fourth Gospel's account of the Lord's Passion is proclaimed. It is very different from the other three accounts in Matthew, Mark, and Luke. Listen to how much Jesus is really "in charge" here. He is quite bold about his mission, his self-image as God, and his fearlessness in facing the earthly governing powers.
Try to be among the first to venerate the cross and return to your place. Notice the reverence with which your fellow Catholics approach the cross and venerate it themselves; notice their ages and their awe before this symbol of both death and life.
These words of the late Father Thomas Savage, SJ, might be a meditation for that day: "The body of the historical Jesus no longer hangs upon the cross. The cross is here so that the triumph, which took place in Jesus once and for all, might continue to happen in his body -- so that his triumph might take place in us, in our lives and in our death. In this hope, let us come to embrace the cross."
The Easter Vigil in the Holy Night
The four parts of this liturgy: the Service of Light, the Liturgy of the Word (much longer than usual), the Liturgy of Baptism, and the Liturgy of the Eucharist are celebrations of who we are. The Church, a pilgrim people of God, the Body of Christ on our way to the kingdom, enlightened by Christ, instructed by his word, given new life with him in the waters of baptism, and strengthened by him with the Eucharist, we are sent on the mission of bringing this Good News to others by word and deed.
Much preparation goes on before the celebration of the Triduum. If you are involved directly with the preparations and can step back a bit from it all, take a breath, and get a bit of quiet time. It'll help you appreciate what we do at the Triduum. It'll also help you realize what you do to get everyone and everything ready for it is invaluable.
If you are in the assembly during the Triduum, take a minute to say a prayer of thanks to God for all the unseen folks and their work who make the "Three Great Days" days of prayer, truly holy days.
This brief overview of the Triduum might lead you to search for more about these holy days. Some of the following are recommended for those concerned with the preparation of the Triduum and its celebration, others for a more meditative and personal preparation.
Good starting point (following familiarity with the Roman Missal and Lectionary)
Our friends on the Pacific Coast at the Office for Divine Worship in Los Angeles (lacatholics.org/liturgical-lent-resources/) provide multiple resources available in both English and Spanish. Sign up for their newsletter. It's free.
Parishes can check the following: ltp.org/products/details/EGCHWT/guide-for-celebrating-holy-week-and-the-triduum; and litpress.org/Products/6242/Glory-in-the-Cross (always safe to turn to Turner); litpress.org/Products/4602/Three-Great-Days
For those who want to venture into a "spiritual journey" with Christ through his death and to his resurrection, "Awesome Glory: Resurrection in Scripture, Liturgy, and Theology" by Abbot Jeremy Driscoll OSB, should not be missed.