Hospitality is to be a generous and friendly host and a respectful and pleasant guest; it means we must be polite with our visitors and grateful with our hosts. This is a reciprocal relationship where we respect, expecting to be respected. It doesn’t signify treating badly a guest already invited but we are not obligated to accept ungracious guests in our home.
This virtue, more than any other, rules the relationship between people. Gifts must be paid with gifts, for a virtuous guest is appreciative and thankful for his host and returns his welcome with pleasant moments and gracious retributions. Hospitality is to be generous with honorable and worthy people, and only people who show their merit are deserving of this bountiful asset.
Hospitality is to know how to give and receive; it is a form of social interaction, and an act of expanding relationships. It is a manner of sharing a little of the best we have and our time with others.
I think Hospitality is a rule to regulate the interaction with the gods too. Hospitality to the gods means to maintain a constant practice of offerings and a pious way of acting not only when religious guesting and feasting are being made, but as a general conduct, for the gods are not restricted to temples and events, they are in every little piece of our lives and world. Honoring the gods with gifts is to sustain a mutual connection of affinity and to strengthen the alliance with the Otherworld. Therefore this Virtue is a fundamental one, for it is the basis to all the social interaction in all kind of relations; material or spiritual.