On the authority of Abu Hurayrah (may Allah be pleased with him), that the Messenger of Allah (peace and blessings of Allah be upon him) said:
Let him who believes in Allah and the Last Day speak good, or keep silent; and let him who believes in Allah and the Last Day be generous to his neighbour; and let him who believes in Allah and the Last Day be generous to his guest.[Al-Bukhari][Muslim]
Reference: 40 Hadith Nawawi 15
English translation: Hadith 15