(1) بَابُ مَا جَاءَ فِي إِجَازَةِ خَبَرِ الْوَاحِدِ الصَّدُوقِ فِي الأَذَانِ وَالصَّلاَةِ وَالصَّوْمِ وَالْفَرَائِضِ وَالأَحْكَامِ
Narrated `Umar:
There was a man from the Ansar (who was a friend of mine). If he was not present in the company of Allah's Messenger (ﷺ) I used to be present with Allah's Messenger (ﷺ), I would tell him what I used to hear from Allah's Messenger (ﷺ), and when I was absent from Allah's Messenger (ﷺ) he used to be present with him, and he would tell me what he used to hear from Allah's Messenger (ﷺ) .
Reference: Sahih al-Bukhari 7256
In-book reference: Book 95, Hadith 11
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 9, Book 91, Hadith 362