Sunan an-Nasai 19764
In-book no 5028أَخْبَرَنَا إِسْمَعِيلُ بْنُ مَسْعُودٍ قَالَ حَدَّثَنَا خَالِدٌ يَعْنِي ابْنَ الْحَارِثِ عَنْ شُعْبَةَ عَنْ عَبْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ بْنِ جَبْرٍ عَنْ أَنَسٍ عَنْ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ حُبُّ الْأَنْصَارِ آيَةُ الْإِيمَانِ وَبُغْضُ الْأَنْصَارِ آيَةُ النِّفَاقِ
It was narrated from Anas that: The Prophet said: "Love for Ansar is a sign of Faith, and hatred for Ansar is a sign of hypocrisy."