Sayyiduna al-Harith bin Ziyad (may Allah be pleased with him) said: I heard the Messenger of Allah (peace and blessings be upon him) say: "Whoever loves the Ansar, Allah will love him when he meets Him; and whoever hates the Ansar, Allah will hate him when he meets Him."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 3345