Sayyiduna Abu Shurayh (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) said: "Whoever believes in Allah and the Last Day, let him honour his guest; and whoever believes in Allah and the Last Day, let him treat his neighbour well; and whoever believes in Allah and the Last Day, let him speak good or remain silent."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9178