Musannaf Ibn Abi Shaybah

Hasan says that when you hear the voice of the muezzin, say the same words that the muezzin says. However, when he says "Hayya 'ala-s-Salah," you should say, "La hawla wa la quwwata illa billah." When he says "Qad qamatis salah," you should say these words: "O Allah! O Lord of this perfect call and the prayer that is to be established after it! Grant Muhammad (peace be upon him) on the Day of Resurrection that which he has asked of You." Whoever supplicates with this prayer at the time of Iqamah, Allah will include him in the intercession of the Prophet (peace be upon him) on the Day of Resurrection.