What does Genesis 18:3 mean?

Abraham, seeing three unexpected strangers standing near his tent in the heat of the day, rushes toward them, bows low before them, and earnestly asks them not to pass by. He practically begs the leader of the group to stop and spend time with him.

According to earlier verses, these three men are actually God, in a physical form, and a pair of angels. It remains unclear, still, if Abraham understands that the leader of these three is indeed the Lord. His language would certainly be appropriate for addressing God. He calls Him Lord, asking Him to stop if Abraham has found favor in His eyes.

However, Abraham's respectful language may also represent the appropriate and gracious standard for welcoming strangers in his part of the ancient world. That culture placed an enormous value on social graces, including respect. This style of modest speech would have been the norm when dealing with strangers.