EXOD280 I would not know who bowed down to whom, and who kissed whom, if not for the fact that it is written: "And a man inquired of the other's well-being." Who is called "a man"? Moses, as it is written (Numbers 12:3): "And the man, Moses, was exceedingly humble" -- whence it is seen that it was Moses, who bowed down to and kissed his father-in-law. From here is derived that one must be solicitous of the honor of his father-in-law (Mechilta).