What does Genesis 18:8 mean?
Finally the meal is ready for Abraham's three visitors, one of whom is the Lord in human form. In the previous verses, Abraham rushed to prepare a royal feast. This included an enormous amount of bread made from fine flour (Genesis 18:6) and a young calf quickly slaughtered and prepared (Genesis 18:7). Now Abraham presents the food, along with some curds and milk, likely a kind of yogurt.Acts of generous hospitality, along with the contents of the meal, would have been standard among the Bedouin people of the time. It would also have been normal for the host to stand back and allow his guests to eat in peace without him. For this reason, some scholars suggest Abraham may not have known, yet, that this stranger was actually the Lord. According to this view, Abraham was merely exhibiting the qualities of a generous and kind-hearted host. At the same time, Abraham's hospitality here is extravagant.
In either case, Abraham will clearly come to understand who his guest is in the following verses.