Genesis 18:4
wash ... feet <07272 07364> [wash your feet.]
In those ancient times, shoes such as ours, were not in use; and the foot was protected only with sandals or soles, fastened round the foot with straps. It was, therefore, not only necessary from motives of cleanliness, but also a very great refreshment, in so hot a country, to get the feet washed at the end of a day's journey; and this is the first thing that Abraham proposes.
tree <06086> [tree.]
Rest in the shade was the second requisite for the refreshment of a weary traveller.