Washing another's feet

The Washing of the Feet by Ghislaine Howard

It is a very strange biblical story. Before the Last Supper, Jesus began to wash the disciples' feet. Apostles get greatly disturbed by it. Peter didn’t understand it at all, he refused. But Jesus explained it for him. The event is narrated in John 13:
13 You call me 'teacher' and 'master,' and rightly so,
for indeed I am.  
14 If I, therefore, the master and teacher, have washed your feet, you ought to wash one another's feet.  
15 I have given you a model to follow, so that as I have done for you, you should also do.
16 Amen, amen, I say to you, no slave is greater than his master nor any messenger greater than the one who sent him.
What does this mean? In many cultures, the feet are considered the lowest, most impure part of the body. Lifting up the foot to expose the sole is an especially offensive gesture in the Middle East. But in Hinduism, for a person to touch the feet of a guru or elder, for students to touch the feet of their teacher, or for children to touch the feet of their parent is a gesture of obeisance. But here, in biblical story, we see an opposite case. The highest must be at the service of others. This is a great symbol, right?
Usually it is treated as a humility example. And it is true, certainly. True humility is always grounded in the truth. The humility will tear down our pride and that is necessary for any real spiritual life.
In a broad sense, it's about service, self-giving love. When "You received without payment; give without payment."( Matt 10:8)
But I have steady feeling of there is something more. For example, can be it connected somehow with wedding ritual? 

Throughout the Middle East the washing of the feet is part of betrothal and marriage ceremonies. It symbolises not only the self-giving love but one more important thought:
your hands are my hands and your feet are my feet because

we are one body.