Warm welcome extended to visitors: part of the AncientCustom(s) of Mankind.
I like the Arabic welcome at the door:
'Bayt-i Bayt-kum': 'My house is your house'. Seems quite appropriate to Wiki.
The SpanishLanguage? adopted this saying, doubtless a result of Moorish influence.
Peter Jones' excellent Learn Ancient Greek (ISBN 0715627589 ) reveals that /xenos/ meant both "stranger" and "guest".
Zeus, the king of the gods, was also the god of hospitality and protector of guests. They took it /very/ seriously.
That does the nice second meaning for the word "xenophobia"...
See also StBenedictsRule