(36) باب مَا يَقُولُ إِذَا سَمِعَ الْمُؤَذِّنَ
'A'ishah said that when the Messenger of Allah (ﷺ) heard the MU'ADHDHIN uttering the testimony, he would say:
"And I too, and I too".
Reference: Sunan Abi Dawud 526
In-book reference: Book 2, Hadith 136
English translation: Book 2, Hadith 526