Musannaf Ibn Abi Shaybah 2384 — What a man says when he hears

Al-Awza'i said: When Mujahid heard 'Hayya 'ala al-salah' (Come to prayer), he would say: 'Al-musta'anu Allah' (Help is sought only from Allah), and when the muezzin said 'Hayya 'ala al-falah' (Come to success), he would say: 'La hawla wa la quwwata illa billah' (There is no might nor power except with Allah).