Wash your feet before you eat

When we were young our parents stressed the importance of always washing our hands before we eat.  In the Bible it was customary for a host to offer his guests water so they could wash their feet before eating.

Abraham lifted up his eyes and looked, and behold, three men were standing in front of him. When he saw them, he ran from the tent door to meet them and bowed himself to the earth and said, “O Lord, if I have found favor in your sight, do not pass by your servant. Let a little water be brought, and wash your feet, and rest yourselves under the tree, while I bring a morsel of bread, that you may refresh yourselves, and after that you may pass on—since you have come to your servant.”

So they said, “Do as you have said.”
Genesis 18:2-5