Xenia.
Xenia (Greek: ξενία) is an ancient Greek concept of hospitality. It is almost always translated as 'guest-friendship' or 'ritualized friendship'.
The Greek god Zeus is sometimes called Zeus Xenios in his role as a protector of strangers. He thus embodied the moral obligation to be hospitable to foreigners and guests. Theoxeny or theoxenia is a theme in Greek mythology in which human beings demonstrate their virtue or piety by extending hospitality to a humble stranger (xenos), who turns out to be a disguised deity (theos) with the capacity to bestow rewards. These stories caution mortals that any guest should be treated as if potentially a disguised divinity and help establish the idea of xenia as a fundamental Greek custom.
Xenia consists of two basic rules:
The respect from hosts to guests. Hosts must be hospitable to guests and provide them with shelter.
The respect from guests to hosts. Guests must be courteous to their hosts and not be a threat or burden.
Xenia was considered to be particularly important in ancient times when people thought that gods mingled among them. If one had poorly played host to a stranger, there was the risk of incurring the wrath of a god disguised as the stranger. It is thought that the Greek practice of theoxenia may have been the antecedent of the Roman rite of Lectisternium, or the draping of couches.
Source: Wiki 2022