It is narrated from Sayyiduna Anas (may Allah be pleased with him) that the Muhajirun said: "O Messenger of Allah, the Ansar have taken away all the reward." He (peace and blessings be upon him) said: "No, not as long as you pray to Allah for them and praise them."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الهبات / 12035
Hadith Gradingمحدثین:اخرجه البخاري في الادب المفرد 217