What does Genesis 18:4 mean?

Abraham, sitting in the door to his tent in the heat of the day, is startled to see three men standing not far from him. One of the men was the Lord in human form, an event referred to as a theophany. The other two are angels. In prior verses, Abraham ran out to greet them, bowed low with great respect, and asked the Lord not to pass by.

Here, Abraham urges them to rest under the shade of the tree, to have some water and have their feet washed. Foot washing was not only a sign of politeness and respect, but also of hospitality. Depending on who did the actual washing—usually a servant—it could also carry a sense of submission.

Abraham's eager hospitality may have been representative of the common attitude towards strangers in his culture, but he was also showing appropriate hospitality to the Lord who had given him the covenant promises and commands of the previous chapter.