"Jesus, knowing that he had come from God and was going back to God, got up and washed their feet." He did something his friends considered unthinkable (Peter: "You will NEVER wash my feet, Jesus!"), taking off his robe and tying a towel around his waist and serving his friends, serving even the one who was to betray him, by washing their feet.
He could do this because he knew he had come from God and was going back to God. He had no doubt, no fear, about that.
What would we do, what could we do, if we knew - truly knew, truly believed, truly lived - this? If we truly knew, believed, lived in the surety that we have come from God and are going back to God, could we do the unthinkable? Could we do something daring and uncharacteristic? Could we serve others, touch others, be in relationship with others, even others we might be afraid of, be wary of, be suspicious of? Could we even wash someone like Judas' feet if we knew that we came from God and were going back to God?
For some reason, we have difficulty believing that as it was true for Jesus, so it is true for us. (Oh, but he's JESUS! And we're not.) And yet, we, too, have come from God and will return to God (for as we say in Eucharistic Prayer A: O God, in your infinite love you made us for yourself) and so we are safe, we are saved, we are free to risk loving and serving not only our friends but our enemies. And we are not diminished by that love or that service, but rather we are freed for that love and that service.
We are, like Jesus, made free by the knowledge that we came from, and will return to, God. And so perhaps what we would do, could do is to feel free to follow Jesus, who said on this night, after he showed them how to do the uncharacteristic, the daring, the unthinkable, "I give you a new commandment: love one another just as I have loved you. The world will see and know that you are my disciples if you have love for one another."
We are safe, we are God's, we are loved. Jesus loved his disciples, he loved even Judas, he loves even us secure in the knowledge that he came from God and would return to God. And so in that knowledge we also can, we also are free to, do something crazy like love.