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 Sahih Muslim 75
Arabic hadith text
وَحَدَّثَنِي زُهَيْرُ بْنُ حَرْبٍ، قَالَ حَدَّثَنِي مُعَاذُ بْنُ مُعَاذٍ، ح وَحَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ مُعَاذٍ، - وَاللَّفْظُ لَهُ - حَدَّثَنَا أَبِي، حَدَّثَنَا شُعْبَةُ، عَنْ عَدِيِّ بْنِ ثَابِتٍ، قَالَ سَمِعْتُ الْبَرَاءَ، يُحَدِّثُ عَنِ النَّبِيِّ صلى الله عليه وسلم أَنَّهُ قَالَ فِي الأَنْصَارِ "لاَ يُحِبُّهُمْ إِلاَّ مُؤْمِنٌ وَلاَ يُبْغِضُهُمْ إِلاَّ مُنَافِقٌ مَنْ أَحَبَّهُمْ أَحَبَّهُ اللَّهُ وَمَنْ أَبْغَضَهُمْ أَبْغَضَهُ اللَّهُ " . قَالَ شُعْبَةُ قُلْتُ لِعَدِيٍّ سَمِعْتَهُ مِنَ الْبَرَاءِ قَالَ إِيَّاىَ حَدَّثَ
Translation
Al-Bara reported from the Messenger (may peace and blessing be upon him) that he remarked with regard to the Ansar
"None but the believer loves them, none but the hypocrite hates them. He who loves them loves Allah and he who hates them hates Allah." I (the narrator) said: Did you hear this hadith from al-Bara'? He said: He narrated it to me.