Genesis 18:4

Wash your feet— It was a custom to wash the feet of guests, deduced from the earliest times to the apostles' days; see ch. Genesis 19:2.Genesis 24:32.Judges 19:21. Hence St. Paul appoints widows to be chosen, 1 Timothy 5:10 if they have lodged strangers, if they have washed the saints' feet. See Luke 7:44.John 13. This must have been a great refreshment in those hot countries, where men travelled barefooted or in sandals only. Rest yourselves under the tree, the oak, or shady grove of oaks, where Abraham's tent was fixed. The heat of the country here again must be considered, which rendered such a shady situation most delightful. Hence that phrase in Scripture, of every man's sitting under his own vine and his own fig-tree.