Jesus saith to him, He that is washed needeth not save to wash his feet, but is clean every whit: and ye are clean, but not all. He that is washed - That is, he who has been in the bath, as probably all the apostles had lately been, in order to prepare themselves the better for the paschal solemnity; for on that occasion, it was the custom of the Jews to bathe twice.
Needeth not save to wash his feet - To cleanse them from any dirt or dust that might have adhered to them, in consequence of walking from the bath to the place of supper. The washing, therefore, of the feet of such persons was all that was necessary, previously to their sitting down to table; The Hindoos walk home from bathing barefoot, and, on entering the house wash their feet again. To this custom our Lord evidently alludes.
If these last words of our Lord had any spiritual reference, it is not easy to say what it was. A common opinion is the following: He who is washed - who is justified through the blood of the Lamb, needeth only to wash his feet - to regulate all his affections and desires; and to get, by faith, his conscience cleansed from any fresh guilt, which he may have contracted since his justification.
Ye are clean, but not all - Eleven of you are upright and sincere; the twelfth is a traitor. So it appears he had washed the feet of all the twelve; but as no external ablutions can purify a hypocrite or a traitor, therefore Judas still remained unclean.