This is a title of respect. Possible meanings are 1) Abraham knew that one of these men was God or 2) Abraham knew that these men came on behalf of God.
Here "found favor" is an idiom that means be approved of or that he is pleased with her. Here "eyes" are a metonym for sight, and sight is a metaphor representing his evaluation. Alternate translation: "if you have evaluated me and approve" or "if you are pleased with me" (See: [[rc://en/ta/man/translate/figs-idiom]] and [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-metaphor]])