Abu Hurairah, radiyallahu 'anhu, reported that the Messenger of Allah, sallallahu 'alayhi wasallam, said:

"Let whosoever believes in Allah and in the Last Day either speak good or be silent. Let whosoever believes in Allah and in the Last Day honour his neighbour. Let whosoever believes in Allah and in the Last Day honour his guest."

[Sahih Muslim]