Musar על שבת 253:4

Whenever one offers hospitality to a wayfarer one must do so with a pleasant countenance. Chazal tell us, “Welcoming guests is greater than greeting the Shechinah” (Shabbos 127a). It is a mitzvah of great importance, for whoever gives bread to a poor man weakens the power of 480 bands of destroying angels, as well as that of Lilis, mother of the sheidim, who is always on the look out for accusations to make against the Jewish people. (See Chapter Ten.)