Sahih Bukhari
To make the Heart Tender (Ar-Riqaq)
Volume: 008 / Book Number: 076 / Hadith Number: 482
Narrated Abu Huraira:
Allah's Apostle said, "Whoever believes in Allah and the Last Day should talk what is good or keep quiet, and whoever believes in Allah and the Last Day should not hurt (or insult) his neighbor; and whoever believes in Allah and the Last Day, should entertain his guest generously."