The Shaykh’s mention of how the Companions transmitted the hadith to those who came after them.

The Shaykh : Let us now return with you to the first era, the era of the Prophet (peace and blessings be upon him), to see how the Companions of the Prophet (peace and blessings be upon him) transmitted the reports of the Messenger to those who came after them, whether they were contemporaries of the Prophet (peace and blessings be upon him) but did not have the honor of his companionship, such as the people of Yemen who were in Yemen during the time of the Prophet (peace and blessings be upon him) and were not able to travel to the Prophet (peace and blessings be upon him). So he sent Mu'adh to them, and he sent 'Ali to them, and he sent Abu Musa al-Ash'ari to them, at varying times.