Exodus 4:27 Commentary: Ramban, Rashbam, Sforno & Or HaChaim

AND HE MET HIM IN THE MOUNTAIN OF G-D. Thus you learn that Mount Sinai is between Midian and Egypt.

לך לקראת משה, to fulfill what G’d had already told Moses, i.e. that his brother Aaron was on the way to meet him joyfully. (verse 14)

לך לקראת משה המדברה, like a student who walks some distance to welcome his teacher even before he arrives in town. The student is what we call the “reception committee.” Aaron being a student of Moses although he was his senior has been confirmed already in verse 16 when G’d told Moses concerning his brother: “you will be his prophet, i.e. mentor.”