Ramban on Exodus 4:27/רמב"ן על שמות ד׳:כ״ז

1AND HE MET HIM IN THE MOUNTAIN OF G-D. Thus you learn that Mount Sinai is between Midian and Egypt.

2AND HE KISSED HIM. Aaron kissed Moses, for Moses the humble one treated his older brother with respect. For this reason, it does not say that they kissed each other.