Adam Clarke

Poureth water into a bason, etc. - This was the office of the meanest slaves. When David sent to Abigail, to inform her that he had chosen her for wife, she arose and said: Behold, let thy handmaid be a Servant, to Wash the Feet of the Servants of my lord, Sa1 25:41. Some of the ancients have supposed that our Lord began with washing the feet of Judas, to inspire him with sentiments of compunction and remorse, to melt him down with kindness, and to show all his disciples how they should act towards their enemies. Dr. Lightfoot supposes he washed the feet of Peter, James, and John only; but this is not likely: the verb αρχεσθαι in the sacred writings, signifies, not only to commence, but to finish an act, Act 1:1; and in the Septuagint, Gen 2:3. There is every reason to believe that he washed the feet of all the twelve. See on Joh 13:9 (note).