Foot Washing

Judging from your question, you may be thinking of the incident recorded in Mark 7:1-23 (in which Jesus was challenged by the Pharisees and Scribes as to why his disciples ate food without ceremonial washing of the hands) and connecting it to the event in John 13:1-16 (in which Jesus is depicted as washing the feet of the disciples).

First, the ceremonial cleansing referred to in Mark 7 finds its origins in Exodus 30:17-21. These were specific instructions given to the first priests of Israel, a procedure they were to follow so as not to be considered "unclean" when they performed their duties. Notice here that both the hands and the feet are specifically mentioned, probably to signify that the priests were to be "clean" in regards to everything they touched (the hands) and everywhere they trod within the Tent of Meeting (the feet). This is not the first time the feet are mentioned in the context of approaching God - a more famous example is when Moses was instructed to remove his sandals as he approached the Burning Bush (Exodus 3:5). For the purpose of answering your question, note especially God's instructions in Exodus 30:21: "This is to be a lasting ordinance for Aaron and his descendants for the generations to come." As you probably already know, Aaron and his descendants were to perform the priestly duties for the nation of Israel.

By the time of the incident in Mark, the Pharisees had greatly expanded the scope of this command to include everyone, and not just for priestly functions. The text (Mark 7:34) explains that this ceremonial "washing" was done whenever they ate, even when they returned from the marketplace. Of course, this was not for purposes of hygiene, as there was no understanding of germ theory in those days. The tradition was intended to prevent the one eating from making himself "unclean" by ingesting food touched by ceremonially "unclean" hands. It's important for us to realize that Jesus wasn't critical of hand-washing or tradition, per se. Rather, he was indicating that the emphasis on this tradition was obscuring people from recognizing that "nothing outside a man can make him 'unclean' by going into him. Rather, it is what comes out of a man that makes him 'unclean'" (Mark 7:15). Not only this, but obsessions with tradition were actually used as a basis to escape the clear commands of God (Mark 7:9-13). So to sum up, Jesus was not opposed to people washing their hands.

In John 13 Jesus demonstrated the extent of his love by washing the feet of the disciples. In those days, when people walked great distances wearing only sandals, the proper etiquette for a host was to arrange for the washing of his guests' feet - and this disagreeable task was the duty of the lowliest servant in the household. This explains Peter's exclamation that "you shall never wash my feet!" For that moment, Peter did not realize the symbolic nature of what Christ was doing - but when Jesus gently corrected him by saying "Unless I wash you, you have no part with me," we see Peter at his best, understanding, in a small way, that this foot washing was illustrative of the cleansing of the believer coming in faith in Christ: "Then Lord, not just my feet but my hands and my head as well!" (v.9).

Jesus did not wash Peter's hands and head - they were, symbolically speaking, "already clean." Some branches of the church today still practice foot washing - it is their belief that it has a sacramental character, instituted by Christ in the same way he established Baptism and Communion, but this is not a widespread, commonly expressed practice. While today we put special emphasis on personal hygiene as it pertains to having clean hands and feet, because of the work of Christ, we are "already clean."