1 Peter 4:9-10

He is said to be hospitable who cheerfully acts the host.  When the Apostles went abroad one with another and preached and sent their younger brethren here and there, it was necessary that one should lodge the other.  How well would it be if, where one was weak he should be helped, and where one had fallen down he should be lifted up.  St. Peter directs that this should take place without murmuring, and that no one should permit it to seem too much for him.

This is also a work of love, that we minister to one another.  With what? With the gifts of God which every one has received.  The Gospel directs that every one be the servant of the other, and in addition, see to it that he abide in the gift which he has received and which God has bestowed upon him; that is, the state and condition of life unto which he has been called.  Although you are a high and great lord, nevertheless you should employ your power to this end, that you may therewith serve your neighbor.  Thus every one should consider himself a servant.  God has not bestowed upon us all the same grace; for this reason every one should inquire to what he has been appointed, and what kind of gift has been bestowed upon him.  When he discovers this, let him use it for the service of his neighbor.

Martin Luther

See also John 13:1-20