Recently, I have fielded some questions on what Maundy Thursday is.  What is quoted here is from CRI Voice.  I discovered it a few years ago, and it is a great source on worship (not so much in regards to music, but in regards to worship and the liturgical year.)  The site is run by Dr. Dennis Bratcher, who also is a professor at several Nazarene Universities.  Here is what he writes about Maundy Thursday.

There are a variety of events that are clustered on this last day before Jesus was arrested that are commemorated in various ways in services of worship. These include the last meal together, which was probably a Passover meal, the institution of Communion, the betrayal by Judas (because of the exchange with Jesus at the meal), and Jesus praying in Gethsemane while the disciples fell asleep. Most services, however, focus on the meal and communion as a way to commemorate this day.

During the last few days, Jesus and His disciples had steadily journeyed from Galilee toward Jerusalem. On the sunlight hillsides of Galilee, Jesus was popular, the crowds were friendly and the future was bright. Even his entry into Jerusalem had been marked by a joyous welcome. But in Jerusalem there was a growing darkness as the crowds began to draw back from the man who spoke of commitment and servanthood. There was an ominous tone in the murmuring of the Sadducees and Pharisees who were threatened by the new future Jesus proclaimed.

Even as Jesus and his disciples came together to share this meal, they already stood in the shadow of the cross. It was later that night, after the meal, as Jesus and His disciples were praying in the Garden of Gethsemane, that Jesus was arrested and taken to the house of Caiaphas the High Priest. On Friday He would die.

Thursday of Holy Week is remembered as the time Jesus ate a final meal together with the men who had followed him for so long. Traditionally in the Christian Church, this day is known as Maundy Thursday. The term Maundy comes from the Latin word mandatum (from which we get our English word mandate), from a verb that means “to give,” “to entrust,” or “to order.” The term is usually translated “commandment,” from John’s account of this Thursday night.  According to the Fourth Gospel, as Jesus and the Disciples were eating their final meal together before Jesus’ arrest, he washed the disciples’ feet to illustrate humility and the spirit of servanthood. After they had finished the meal, as they walked into the night toward Gethsemane, Jesus taught his disciples a “new” commandment that was not really new (John 13:34-35):

A new commandment I give to you, that you love one another; even as I have loved you, you also ought to love one another. By this everyone will know that you are my disciples, if you have love for one another.

The Communion of Maundy Thursday is especially tied to the theme of remembering. As Jesus and his disciples followed the instructions in the Torah to remember God’s acts of deliverance in their history as they shared the Passover meal together, so Jesus calls us to remember the new act of deliverance in our history that unfolds on these last days of Holy week.