Mishkat al-Masabih 1127
Ibn ‘Umar said:
When the first Emigrants came to Medina, Salim the client of Abu Hudhaifa acted as their imam , and ‘Umar and Abu Salama b. ‘Abd al-Asad were among their number. 

Bukhari transmitted it.
وَعَنِ ابْنِ عُمَرَ قَالَ: لَمَّا قَدِمَ الْمُهَاجِرُونَ الْأَوَّلُونَ الْمَدِينَةَ كَانَ يَؤُمُّهُمْ سَالِمٌ مَوْلَى أَبِي حُذَيْفَةَ وَفِيهِمْ عُمَرُ وَأَبُو سَلَمَةَ بْنُ عَبْدِ الْأسد. رَوَاهُ البُخَارِيّ