The concept of guest-friendship prevails consistently in Ancient Literature, a kind of hospitality enforced socially through religion.
Their concept of what hospitality was, however, differs greatly from nowadays. While we may think of hospitality being acting as the host to previously invited guests, or what you expect in the strongly recommended hotel you booked. In ancient times, if someone rocked up on your doorstep and supplicated themselves to you, you are religiously obliged to let them in.
And feed them. And care for them. And etc…
It is clearly presented in literature on being a social norm, and still we study whether a character acts according to xenia or not, including whether the treatment of the Cyclops in Book 9 of the Odyssey is justifiable according to xenia.
Likewise, the Gods, namely Apollo, in one of Herodotus’s tales, force Cyme into caring for their suppliant in defiance of the Persians through giving them erroneous oracular responses so to destroy the Cymeans more quickly for even daring to think of giving up their suppliant.
Likewise, supplication appears in Book 8 of The Aeneid when Aeneas arrives at Pallanteum to see Evander, and in Book 1 of The Iliad when Thetis appeals to Zeus. Countless times supplication appears in literature, showing just how commonplace it was.
It certainly represents a change in society, that caring for strangers used to be an obligation rather than a paid privilege.