Sunan An-Nasai, Chapter: The Book of the Adhan (The Call to Prayer)

from Abu Qilabah, from Amr bin Salamah: "Abu Qilabah said to me (Ayyub): He (Amr) is still alive, do you want to meet him?" I met him and asked him, and he said: "When Makkah was conquered, all the people hastened to announce their Islam. My father went to announce the Islam of the people of our village, and when he came back we went to see him and he said: 'By Allah, I have indeed come to you from the Messenger of Allah (saw).' He said: 'Pray such and such a prayer at such and such a time, pray such and such a prayer at such and such a time. When the time for prayer comes let one of you call the Adhan and let the one who knows the most Quran lead the prayer.'" (Sahih)