Sunan Abu Dawud
537
Sahih+2

Jabir b. Samurah said:Bilal would call the Adhan, then he used come to wait. When he would see that the prophet (ﷺ) had come out (of his house), he would pronounce the iqama

SahihAl-Albani
SahihMuhammad Muhyi Al-Din Abdul Hamid