Avraham Avinu was the forefather of the Nation of Yisroel and one of the three Avos.
Avram was born to Terach the son of Nachor. At the time, Nimrod ruled the world and had managed to turn all mankind to the worship of idolatry.
Avraham used his wealth to build large guest halls at many busy intersections throughout Eretz Yisroel. There his staff would provide free food and drinks to all passerbyes, when they were ready to leave they would be escorted a little for the start of their journey. All the halls as well his personal tent contained entrances on all four sides to make them easily accessible to all visitors.
Ashel is an acronym for Achelah - eating, Shtiya - drinking and Leviyah - escorting. Through the eating Avraham was working on rectifying the sin of Adom, who are from the tree of knowledge. Serving drinks was done to help rectify the sin of Noach who drank from the wine. Escorting the guests was done to help rectify the sin of Sidom who shunned kindness.