To this we can add Nephi's woe:

Wo unto the rich, who are rich as to the things of the world. For because they are rich they despise the poor, and they persecute the meek, and their hearts are upon their treasures; wherefore, their treasure is their god. And behold, their treasure shall perish with them also. (2 Nephi 9:30)

Together Nephi and King Benjamin sum up the Book of Mormon's consistent, insistent reminder that our salvation depends on how we deal with each other, and that our treatment of those who have less than we is the best sign of our dealings in general.

Maundy Thursday also commemorates the Savior's institution of the Eucharist. We call it "the Sacrament":

As they were eating, Jesus took bread, and blessed it, and brake it, and gave it to the disciples, and said, Take, eat; this is my body. And he took the cup, and gave thanks, and gave it to them, saying, Drink ye all of it; for this is my blood of the new testament, which is shed for many for the remission of sins (Mt. 26:26-28).

Mormons celebrate the Sacrament each Sunday, receiving bread and water (in place of wine) that has been sanctified to our souls by the ritual (we say "ordinance"). The prayers said over the Eucharistic elements are given in the Book of Mormon (Moroni 4-5), and they tell us what that sanctification entails: We partake of the bread and water in remembrance of the sacred body and blood of Jesus Christ, who suffered pains in the flesh and was crucified for our sins, and we believe that to eat the bread and drink the water is to witness to God the Father that we are willing to be called by the name of his Son.

To take part in the Sacrament is to testify to God that I am willing to be called a Christian, and to recognize what that willingness entails. As the events in the Upper Room show, they entail service and communion.

With the Sacrament we testify that we will remember Jesus Christ always. We will not just keep his name in mind; we allow our lives to become a memorial to his. We promise also to keep his commandments, another way of saying that we will remember him always. And we understand that by taking part in the Sacrament we are promised his Spirit as a guide and witness.

John 13 helps us see the connection of the two events of that evening, Jesus washing the feet of his apostles and their communal meal culminating (according to Matthew) in the Sacrament. In fact, John helps us see how the two come together in meaning: Jesus shares food with his fellows in an act of memorial and pledge, but he makes that meal possible by stripping himself like a slave and washing their feet in both humility and welcome.