Umar bin Abdullah, the freedman of Ghufrah, said: When Sayyiduna Abu Bakr (may Allah be pleased with him) made his first distribution, Sayyiduna Umar (may Allah be pleased with him) said to him: Give preference to the Muhajirun and to those who were foremost in Islam. Sayyiduna Abu Bakr (may Allah be pleased with him) said: I know (the reward and merit of) those among them who were foremost. So he (may Allah be pleased with him) distributed equally.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الفيء والغنيمة / 12988