Rabbinic literature abounds in statements praising the practice of hospitality on behalf of travelers and indigents. One even calls it "greater than welcoming the Divine Presence [Sh'khinah]."
A midrash presents the biblical patriarch Abraham as the paragon of hospitality, because of his reception of wayfarers in Genesis 18. His position at the entrance of his tent in the midday heat is interpreted as a proactive seeking out of passing travelers. Other elements of the story, too, contribute to Abraham's reputation: his eagerness, his largesse, and his insistence on seeing his guests off as they departed.
The residents of Jerusalem, too, are portrayed in midrashic literature as excelling in this virtue. When the Holy Temple still stood in Jerusalem, that city was the destination of pilgrims from throughout the Land of Israel at the three harvest festivals. The rabbinic storytellers of late antiquity relate that Jerusalem's householders opened their homes for free to those visitors. "No person ever remarked to another, 'I couldn't find a bed to sleep on in Jerusalem.' No person ever remarked to another, 'Jerusalem is too small [i.e., crowded] for me to be able to stay over there'" (Avot de-Rabbi Natan 33).
Not only are food and lodging to be provided for passing travelers, but they must be accommodated graciously. The statement of the early sage Shammai that one should "greet each person with a cheerful facial expression" (Mishnah Avot 1:15) is understood midrashically (in Avot De-Rabbi Natan 13) as an admonition to hosts not to provide for their guests amply but angrily. Better, teaches the midrash, to offer a guest but a little in a gracious tone than large portions obviously proffered grudgingly.