It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "A man who believes in Allah and the Last Day does not hate the Ansar, and a man who believes in Allah and the Last Day does not love Thaqif (the tribe)."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12287