Sahih Muslim 76
Sahih Muslim · Book 1: The Book of Faith · Evidence that love of the Ansar and Ali (r.a.) is a part of faith and a sign thereof; Hating them is a sign of hypocrisy
It is reported on the authority of Abu Huraira that the Messenger of Allah (may peace and blessings be upon him) said:
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ ، حَدَّثَنَا يَعْقُوبُ، - يَعْنِي ابْنَ عَبْدِ الرَّحْمَنِ الْقَارِيَّ - عَنْ سُهَيْلٍ ، عَنْ أَبِيهِ ، عَنْ أَبِي هُرَيْرَةَ ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " لاَ يُبْغِضُ الأَنْصَارَ رَجُلٌ يُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الآخِرِ " .
A person who believes in Allah and the Last Day never nurses a grudge against the Ansar.