Sayyiduna Ibn Umar (may Allah be pleased with them both) narrates: Salim, the freed slave of Abu Hudhayfah (may Allah be pleased with him) used to lead the first Muhajirun, who were the Companions of the Prophet (peace and blessings be upon him), and the Ansar in prayer in the mosque of Quba. Among them were Sayyiduna Abu Bakr and Sayyiduna Umar (may Allah be pleased with them both), Sayyiduna Abu Salamah, Sayyiduna Zayd and Sayyiduna Amir bin Rabi'ah (may Allah be pleased with them).
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6341