1. The Sunnah recommends that while the adhan (call to prayer) is being called, one should listen attentively and repeat every line silently after the Mu’adhin (the one who calls to prayer), but when he says “Hayya ‘ala-Salah” (come to prayer) and “Hayya ‘ala-l-falah” (come to success) one should say:

La hawla wa la quwwata illa billah (There is no might or power except with Allah)

Prophet Muhammad said:

“When you hear the adhan, repeat what the Mu’adhin says.” (Imam Malik – Muwatta)

2. Invoke Blessings to the Prophet (peace be upon him)

The Prophet (peace and blessings be upon him) said:

“When you hear the Mu’adhin calling for the prayer, repeat his words then ask Allah’s blessings upon me, because the one who asks Allah’s blessings upon me once will be rewarded ten blessings by Allah.” (Muslim, The Book of Prayer, Hadith 384)

The text of As-Salawat Al-Ibrahimiah is:

Allahumma salli ala Muhammadin wa ala ali Muhammadin, kama sallayta ala Ibrahima wa ala ali Ibrahima innaka Hameedun Majeed. Allahumma Barik ala Muhammadin wa ala aali Muhammadin kama barakta ala Ibrahima wa ala aali Ibrahima innaka Hameedun Majeed.

(i.e. O Allah, bestow your favor on Muhammad and on the family of Muhammad as You have bestowed Your favor on Ibrahim and on the family of Ibrahim, You are Praiseworthy, Most Glorious. O Allah, bless Muhammad and the family of Muhammad as You have blessed Ibrahim and the family of Ibrahim, You are Praiseworthy, Most Glorious). (Al-Bukhari, The Book of Stories of the Prophet, Hadith 3370)

3. After the Adhan, it is Recommended to Say this Dua (supplication):

Allahumma rabba hadhihi-d-da’awati-t-tammati wa-s-Salati-l-qa’imati, ati Muhammadan il-wasilata wa-l-fadilata (wa-d-darajata-r-rafi’ati) wa-b‘ath-hu maqamam mahmudan illadhi wa‘adtahu (innaka la tukhliful mi’ad).

(O Allah, Lord of this most perfect call, and of the Prayer that is about to be established, grant to Muhammad the favor of nearness (to You) and excellence and a place of distinction, and exalt him to a position of glory that You have promised him.)

This du’a has variations which include ‘wa-d-darajata-r-rafi’ati’ and ‘innaka la tukhlifu’l mi’ad’.

The addition of “innaka la tukhlifu’l mi’ad” in the supplication was narrated by Imam Bayhaqi in his Sunan, and accepted for action by the scholars, as mentioned by Ibn Abidin in Radd al-Muhtar, quoting Shurunbulali’s Imdad al-Fattah and Ibn al-Humam’s Fath al-Qadir.

Narrated by Jabir bin ‘Abdullah: Allah’s Messenger (peace and blessings be upon him) said:

“Whoever after listening to the adhan says (dua is given above) then intercession for me will be permitted for him on the Day of Resurrection“. (Sahih Bukhari – Book 11:588)

Abdullah bin `Amr bin Al-`As reported: I heard the Messenger of Allah (peace be upon him) saying:

“When you hear the Adhan, repeat what the Mu’adhin says. Then ask Allah to exalt my mention because everyone who does so will receive in return ten rewards from Allah. Then beseech Allah to grant me Al-Wasilah (which is said in the dua above), which is a high rank in Jannah, fitting for only one of Allah’s slaves; and I hope that I will be that man. If anyone asks Al-Wasilah for me, it becomes incumbent upon me to intercede for him.” (Sahih Muslim)

4. The Hearer should Say after Hearing Adhan:

Wa anaa ‘ash-hadu ‘an laa ‘ilaaha ‘illallaahu wahdahu laa shareeka lahu wa ‘anna Muhammadan ‘abduhu wa Rasooluhu, radheetu billaahi Rabban, wa bi-Muhammadin Rasoolan wa bil’islaami deenan.

(And I also bear witness that there is no deity has the right to be worshipped but Allah alone, Who has no partner, and that Muhammad is His slave and His Messenger. I am pleased with Allah as my Lord, with Muhammad (peace be upon him) as my Messenger and with Islam as my religion.)

(To be recited in Arabic after the Mu’aththin’s Tashahhud or the words of affirmation of Faith) (Muslim, The Book of Prayer, Hadith 386).

5. Make Dua to Allah in between the Adhan and Iqamah

Finally, you can ask Allah the Almighty anything for yourself and ask the grace of Allah because your supplication will be answered this time.

The Prophet Muhammad (peace and blessings be upon him) said:

“Repeat the words of the Muadhin and when you finish, ask Allah what you want and you will get it” (Abu Dawud, The Book of Prayer, Hadith 524)

(“Kitab As salat” Dawud :: Book 2 : Hadith 521) Narrated Anas ibn Malik:

“The supplication made between the adhan and the iqamah is not rejected”.

Summary of What We Should Do upon Hearing the Adhan

1. Stay focused on the adhan.
   2. Repeat what the muadhin say except for the hayya alas-salah and hayya-ala-falah. Instead say la hawla walakuata illa billah.
   3. After adhan sends salah to Prophet Muhammad (peace and blessings be upon him)
   4. Then say the dua’ wasilah
   5. Make dua between azan and iqamah.

Source: My.opera.com