Sahih al-Bukhari 4897
Sahih al-Bukhari · Book 65: Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh)) · The Statement of Allah ta'ala: "And [He has sent him (Prophet Muḥammad pbuh) also to] others among them (Muslims) who have not yet joined them..." (V.62:3)
Narrated Abu Huraira:
حَدَّثَنِي عَبْدُ الْعَزِيزِ بْنُ عَبْدِ اللَّهِ ، قَالَ حَدَّثَنِي سُلَيْمَانُ بْنُ بِلاَلٍ ، عَنْ ثَوْرٍ ، عَنْ أَبِي الْغَيْثِ ، عَنْ أَبِي هُرَيْرَةَ ، رضى الله عنه قَالَ كُنَّا جُلُوسًا عِنْدَ النَّبِيِّ صلى الله عليه وسلم فَأُنْزِلَتْ عَلَيْهِ سُورَةُ الْجُمُعَةِ {وَآخَرِينَ مِنْهُمْ لَمَّا يَلْحَقُوا بِهِمْ} قَالَ قُلْتُ مَنْ هُمْ يَا رَسُولَ اللَّهِ فَلَمْ يُرَاجِعْهُ حَتَّى سَأَلَ ثَلاَثًا، وَفِينَا سَلْمَانُ الْفَارِسِيُّ، وَضَعَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَدَهُ عَلَى سَلْمَانَ ثُمَّ قَالَ " لَوْ كَانَ الإِيمَانُ عِنْدَ الثُّرَيَّا لَنَالَهُ رِجَالٌ ـ أَوْ رَجُلٌ ـ مِنْ هَؤُلاَءِ " .
While we were sitting with the Prophet (ﷺ) Surat Al-Jumu'a was revealed to him, and when the Verse, "And He (Allah) has sent him (Muhammad) also to other (Muslims).....' (62.3) was recited by the Prophet, I said, "Who are they, O Allah's Messenger (ﷺ)?" The Prophet (ﷺ) did not reply till I repeated my question thrice. At that time, Salman Al-Farisi was with us. So Allah's Messenger (ﷺ) put his hand on Salman, saying, "If Faith were at (the place of) Ath-Thuraiya (pleiades, the highest star), even then (some men or man from these people (i.e. Salman's folk) would attain it."