What is the ruling on the Mu'adhin (caller to Prayer) who says upon finishing Adhan: "Peace and blessings be upon you (Muhammad), the first of the creation and the seal of the messengers of Allah"?
We know of no evidence from the Qur'an or Sunnah that supports the permissibility of saying this statement after finishing Adhan. All good lies in following the tradition of the Messenger (peace be upon him), while all evil lies in going against his tradition. It is authentically narrated that the Messenger of Allah (peace be upon him) said,
Anyone who does an action which is not in accordance with this matter of ours (Islam) will have it rejected.
Upon finishing Adhan, it is permissible for the Mu'adhin and others to invoke peace and blessings upon the Prophet (peace be upon him), and say "O Allah, Lord of this perfect call (Da`wah) and of the established Salah, grant (Part No. 6; Page No. 102) Muhammad the Wasilah and superiority, and raise him up to a praiseworthy position which You have promised him." This is based on the report in which the Prophet (peace be upon him) said,
When you hear the Mu'adhin, repeat what he says, then invoke peace and blessings upon me, for everyone who invokes peace and blessings on me will receive ten blessings from Allah; then beg from Allah Al-Wasilah for me, which is a rank in Jannah (Paradise) befitting for only one of Allah's servants, and I hope that I may be that one. If anyone asks that I be given the Wasilah, he will be assured of my intercession.
The Prophet (peace be upon him) further said,
"Whoever says upon hearing the Adhan, 'O Allah, Lord of this perfect call (Da`wah) and of the established Salah, grant Muhammad the Wasilah and superiority, and raise him up to a praiseworthy position which You have promised him', it becomes incumbent upon me to intercede for him on the Day of Resurrection.''
Al-Bukhari in his Sahih.
Al-Bayhaqy also reported this Hadith with sound chain of narrators and added at the end of the report:
"You do not break Your promise."
It should be noted that this Du`a' has to be said by the Mu'dhin or others in a quiet voice due to the narration mentioned above that provides no support to saying this Du`a' loudly.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.