John 13:15-17

For I have given you an example—you should do just as I have done for you.  I tell you the solemn truth, the slave is not greater than his master, nor is the one who is sent as a messenger greater than the one who sent him.  If you understand these things, you will be blessed if you do them.

This is the lesson after Jesus washes the disciples' feet. Understanding comes with responsibility, and disciples of Christ must carry out the example that Christ set for them. If washing the feet of these men was not too lowly of a job for God the Son, then we can surely serve whatever the situation. As the messengers Christ has sent out into the world, we are to be willing to serve the least important, the lowest of the low. Whatever we do for the least of these, we do for Jesus. Whatever we do not do for the least of these, we refuse to do for Jesus. (Matthew 25:40 & 45 paraphrased)