Not having bought a loin cloth myself, the power of the metaphor seems to diminish, but let us walk through the metaphor to see what it might mean. The loin cloth was meant to be part of God’s array. It was meant to be near to the most vulnerable part of the body. Nearness expresses a sense of vulnerability and affection. The loins in scripture resemble the heart and the way in which people talk about their hearts. Such as when John Wesley declared his heart was strangely warmed. So a covering of the loins would be a pride of place for this article of clothing. Instead of serving as it should, the loin cloth has been balled up like a useless rag and hidden in a cleft of a rock. So Israel, rather than cling to God, has sought solace in a foreign place, and having done so, they have lost their usefulness to God. For Israel, their purpose in the world relies upon it’s fidelity to God. Lose that, and lose direction and meaning.
Pride motives Israel. Love motivates God. So Israel must again face humiliation at the hands of a super power, another Egypt. History repeats itself for those unwilling to listen to the wisdom of the past. Where Israel sees this exile as the end, God sees this as the way forward to humility, a way back to fidelity, a way back to love.
In Jeremiah, we see a people to stubborn to serve God. In John, we see a God/Man so humble he is willing to wash feet. Many scholars now argue that the gospels picture Jesus as Israel. Jesus does what Israel could not do. Paul shows in Romans that no one else could have done it either – see Romans 1:18-25. Jesus loves without regard to social roles, taking the lowest job imaginable, feet washer. Horrified, the disciples refuse. The lessons of pride and humility from their past have yet to be understood. So either be washed or have no part of what Jesus is about. Jesus extends that warning to include the roll of servant. Serve as Jesus did or have no part of Jesus. Strong a statement as that is, consider the humility it requires to acknowledge that you serve God and not yourself. To do more than lip service to this notion, Jesus asks us to serve our neighbor as a way to show that we indeed love God.
BUT what remains a mystery is that the writer tells us that Jesus loved his own, and loved them to the end. The next line tells us that Judas has gone to betray Jesus. Jesus’ love for Judas has not changed, though Judas has changed. Jesus sees the writing on the wall and knows what is in Judas’ heart, but Jesus still loves him. No matter how stubborn, how prideful, how greedy, one might become, Jesus will still wash one’s feet. Jesus will still clean, restore, and make new. How mysterious and marvelous!