A true friend is one whom you know will receive you into his home, even unannounced.
He will of course have some reasonable expectations (e.g. reciprocity), but he will always have a place for you.
A friend in need is a friend indeed!
To elaborate on the Magisterium of the Catholic Church is our mission on Plinthos (Gk. "brick"); and to do so anonymously, so that, like any brick in the wall, we might do our little part in the strength of the structure of humanity almost unnoticed.