Before the feast of Passover, Jesus knew that his hour had come to pass from this world to the Father. He loved his own in the world and he loved them to the end. The devil had already induced Judas, son of Simon the Iscariot, to hand him over. So, during supper, fully aware that the Father had put everything into his power and that he had come from God and was returning to God, he rose from supper and took off his outer garments. He took a towel and tied it around his waist. Then he poured water into a basin and began to wash the disciples' feet and dry them with the towel around his waist. He came to Simon Peter, who said to him, "Master, are you going to wash my feet?" Jesus answered and said to him, "What I am doing, you do not understand now, but you will understand later."
Peter said to him, "You will never wash my feet." Jesus answered him, "Unless I wash you, you will have no inheritance with me." Simon Peter said to him, "Master, then not only my feet, but my hands and head as well." Jesus said to him, "Whoever has bathed 6 has no need except to have his feet washed, for he is clean all over; so you are clean, but not all." For he knew who would betray him; for this reason, he said, "Not all of you are clean."
So when he had washed their feet (and) put his garments back on and reclined at table again, he said to them, "Do you realize what I have done for you? You call me 'teacher' and 'master,' and rightly so, for indeed I am. 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. (John 13:1-15)
Sometimes it is said and written that, unlike the synoptic Gospels (i.e., Matthew, Mark, Luke), John's Gospel has no institution narrative. Of course, John's Gospel has no account of Jesus taking bread, blessing it, and saying "Do this in memory of me," and then taking the cup and saying it is His blood, the blood of the new and everlasting covenant, etc. On the contrary, the first fifteen verses of the thirteenth chapter of this Gospel constitute the Johannine institution narrative. This is but one of many reasons we need four Gospels. This also shows us that Mass is not an end itself.
Typically, at the end of the Mass we are dismissed- The Mass is ended go in peace! Hence, we are sent forth to give witness to the One who dwells in us, to make Him present everywhere we go. At the end of the Mass of the Lord's Supper, however, we are not dismissed. In fact, we are not dismissed again until the end of the Great Vigil late Saturday night, or even early Sunday morning. This is not merely an invitation to prayer, but a summons to enter more deeply into the Paschal Mystery, the great mystery of our redemption, wrought by Jesus Christ, our Passover and our Peace, to reflect deeply on what implications this has for our lives, which, as with John's institution narratives, calls us to a life of self-emptying service to others in imitation of the One whose disciples we are.
Unless I wash you, you will have no inheritance with me