John 13:14

If I then (ei oun egw). Argumentative sense of oun (therefore). Condition of first class, assumed to be true, with first aorist active indicative of niptw, "If I, being what I am, washed your feet" (as I did). Ye also ought (kai umei opeilete). The obligation rests on you a fortiori. Present active indicative of the old verb opeilw, to owe a debt ( Matthew 18:30 ). The mutual obligation is to do this or any other needed service. The widows who washed the saints' feet in 1 Timothy 5:10 did it "as an incident-of their hospitable ministrations" (Bernard). Up to 1731 the Lord High Almoner in England washed the feet of poor saints (pedilavium) on Thursday before Easter, a custom that arose in the fourth century, and one still practised by the Pope of Rome.