There are some very good Christians that practice foot-washing. Is this wrong? Of course not. How could doing something that Jesus did be wrong? The real questions should be: Is it wrong not to practice foot-washing?
The dusty and dirty conditions of the region where Jesus lived necessitated foot-washing. I am sure that the disciples would have been happy to wash Jesus’ feet, however, they could not conceive of washing each other’s feet. In their society foot-washing was reserved for the lowliest of menial servants. The disciples were arguing about who was the greatest among them. When Jesus moved to wash their feet (John 13:1-16), they were shocked. His actions served as a symbolic spiritual cleansing (vs. 6-9) and a model of Christian humility (vs. 12-17).
The foot-washing was an example. Today Christ might have shined the shoes of the disciples. This is not an ordinance of the church. Baptism and the Lord’s supper were practiced repeatedly by the New Testament Churches, foot-washing by the early church is not mentioned.
A Christian widow’s practice of “washing the feet of the saints” (I Timothy 5:10) speaks not of her involvement in a church ordinance but of her humble service to other believers. She displayed inner humility, not a physical rite.