Albert Barnes on John 13:5

Began to wash, &c. It was uniformly the office of a servant to wash the feet of guests, 1Sam 25:41. It became a matter of necessity where they travelled without shoes, and where they reclined on couches at meals. It should be remembered here that the disciples were not sitting at the table, as we do, but were lying with their feet extended from the table, so that Jesus could easily have access to them. Mt 23:6.