Note 9 at Joh 13:15: The example that Jesus was referring to is the example of humility that He showed in serving His disciples. Our Lord was not instituting a new ritual of washing one another's feet that is to be observed by the church.

In that day, people wore sandals, and their feet would become very dirty as they walked or rode donkeys over dusty trails. Therefore, it was a very practical custom that they had of washing guests' feet when they entered the house. This was usually done by a servant or slave.

Jesus simply used this custom to teach some very powerful lessons (see note 4 at Joh 13:5 and note 7 at Joh 13:10). The custom has no virtue in itself, and if the ritual of "foot-washing" is emphasized at the expense of the lesson, then washing someone's feet becomes a meaningless tradition.

Jesus could have taught His lesson by preparing or serving food instead of being served. Likewise, we can follow His example through humbling ourselves and serving others in many different ways.