What does John 13:5 mean?

In the ancient world, washing of feet was not a quick, tidy, or glamorous task. People walked on roads covered in dirt and manure, wearing open sandals. In most cases, people cleaned their own feet. Sometimes, mostly to show hospitality or honor, it would be done by someone else. The foot-washer would have to sit or kneel in front of the person being cleaned. In the prior verse, Jesus changes clothes in order to take on this grimy, humble chore.

In that time and place, such a task was always performed by the person of lower status. The disciples have expressed arrogance and hunger for power (Mark 9:34; Luke 9:54), but they have never wavered in considering Jesus to be their Lord and Master. So His action here is a direct attack on assumptions about power and leadership. In the upcoming verses, Jesus will explain this in no uncertain terms. He is the Master (John 13:13), yet He acts in humility. Those who claim to follow Christ are not better than Christ, so they are not above serving other people (John 13:14–16).

The Greek words used in this passage carry meanings that can be missed in an English translation. These verses describe what Jesus does to the feet of the disciples using the root word niptō, corresponding to the English "wash." When explaining how this is different from a single, total-body cleansing in verse 10, Jesus instead uses the root word louō, corresponding to the English "bathe." Jesus will make a comment in verses 10 and 11, using Judas as an example, which highlights the difference between a person's once-for-all salvation and their subsequent confession of sin.