Sunan Abi Dawud Book 2, Hadith 145
Ibn Umm Maktum was the mu'adhdhin of the Messenger of Allah (May peace be upon him) and he was blind.
The Messenger of Allah (ﷺ) said to Bilal: Do not call adhan until the dawn appears clearly to you in this way, stretching his hand in latitude.
Abu Dawud said: Shaddad did not see Bilal.
we were sitting with Abu Hurairah in the mosque. A man went out of the mosque after the ADHAN for the afternoon prayer had been called. Abu Hurairah said: As regards this (man), he disobeyed Abu al-Qasim, the prophet (ﷺ).