[Machine] Al-Shifa informed me that Labeed bin Rabeeah and Adi bin Hatim, who were among the first migrants, arrived in Medina and came to the mosque. They found Amr bin Al-Aas, and said to him, "O son of Al-Aas, seek permission for us to see the Commander of the Faithful." He replied, "By Allah, you have both hit the mark, for his name is the Commander, and we are the believers." So, Amr bin Al-Aas went in to see Umar and said, "Peace be upon you, O Commander of the Faithful." Umar asked him, "What is this?" He replied, "You are the Commander, and we are the believers." From that day, the title of 'Commander of the Faithful' spread.  

أَخْبَرَتْنِي الشِّفَاءُ بِنْتُ عَبْدِ اللهِ وَكَانَتْ مِنَ الْمُهَاجِرَاتِ الْأُوَلِ أَنَّ لَبِيدَ بْنَ رَبِيعَةَ وَعَدِيَّ بْنَ حَاتِمٍ قَدِمَا الْمَدِينَةَ وَأَتَيَا الْمَسْجِدَ فَوَجَدَا عَمْرَو بْنَ الْعَاصِ فَقَالَا يَا ابْنَ الْعَاصِ اسْتَأْذِنْ لَنَا عَلَى أَمِيرِ الْمُؤْمِنِينَ فَقَالَ أَنْتُمَا وَاللهِ أَصَبْتُمَا اسْمَهُ هُوَ الْأَمِيرُ وَنَحْنُ الْمُؤْمِنُونَ فَدَخَلَ عَمرٌو عَلَى عُمَرَ فَقَالَ السَّلَامُ عَلَيْكَ يَا أَمِيرَ الْمُؤْمِنِينَ فَقَالَ لَهُ عُمَرُ مَا هَذَا؟ فَقَالَ أَنْتَ الْأَمِيرُ وَنَحْنُ الْمُؤْمِنُونَ فَجَرَى الْكِتَابُ مِنْ يَوْمَئِذٍ