Summary: Jesus comforts his disciples with the promise of persecution: if the world hates me, it will hate you too because you are with me.
To properly interpret anything from John 13-17 we’ve got to keep the whole section in mind. The focus in these four chapters is surprisingly narrow as John works toward his stated goal: “these are written, that ye might believe that Jesus is the Christ, the Son of God; and that believing ye might have life through his name” (20:31). Everything before chapter 13 describes how God became flesh, came to earth, and performed miracles to prove himself. He turned water into wine, healed the sick, cast out demons, and even raised the dead.
Most people were amazed and followed him until he revealed his true identity, and then he was largely abandoned and abused. There were, however, several who believed and continued with him, and some of these are present in chapters 13-17. What they don’t know is that the hatred against their master is so complete that the Jewish leaders intend to crucify him the next day. The disciples hang their hopes on him as God’s Messiah, and they believe he’ll establish his kingdom on the earth and restore David’s rule, so they’re going to feel particularly defeated and alone when things don’t go as planned.
Jesus knows this, and he wants to prepare them and give them confidence, so he brings them into this private guest chamber and begins to explain some of the things they haven’t been able to understand. He wants them to know that his death is both planned and necessary. He wants them to know that it doesn’t mean failure and to see that it’s just one step in the plan. There’s much more to follow, and the result is their salvation; “if I go and prepare a place for you, I will come again, and receive you unto myself; that where I am, there ye may be also” (14:3).
This salvation is his purpose in coming, but he has to find a way to tell them how it’s achieved. He has to take them past earthly things and help them see the spiritual.
To do this he takes off his robes and washes their feet.
That might sound strange; how will this help them? What spiritual truth is revealed in foot-washing? Consider what he says immediately after: “Ye call me Master and Lord: and ye say well; for so I am. 14If I then, your Lord and Master, have washed your feet; ye also ought to wash one another’s feet” (13:13-14). In his example Christ defines a divine principle: servants follow their masters. In another part of the book he teaches the same thing to the Pharisees:
Ye do the deeds of your father. Then said they to him, We be not born of fornication; we have one Father, even God. 42Jesus said unto them, If God were your Father, ye would love me: for I proceeded forth and came from God; neither came I of myself, but he sent me. 43Why do ye not understand my speech? even because ye cannot hear my word. 44Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it. 45And because I tell you the truth, ye believe me not (Jn. 8:41-45).