In The Name of Allaah, The Most Merciful, The Bestower of Mercy.
Indeed, there are numerous texts about the A’dhaan- the call to the prayer and an announcement of its beginning time through specific wordings- in the Sunnah of the noble Prophet [sallal-laahu-alayhi-wasallam], which demonstrates its virtue, great importance, beneficial [outcomes] and worth, for both the Mu’adh-dhin and the one who hears it.
[Imam] Al-Bukhaari [rahimahullaah] reported from Abu Sa’eed Al-Khudriy [radiyallaahu-anhu] who said: ‘’Whoever hears the Adhaan, whether a human being, a Jinn or any other creature will be witness for you on the Day of Judgement.’’ [Sahih Al-Bukhari Book of Adhaan. Chapter: Raising the voice in pronouncing the Adhaan. Hadeeth Number 609]
In this hadeeth, there is evidence to show that everyone who hears the voice of the Mu’adh-dhin – whether a human being, a Jinn, a tree, a stone or the animals -will bear witness for the Mu’adh-dhin on the day of judgement. And in this evidence [to show] that it is recommended to raise one’s voice when calling the Adhaan so that those who witness for him become numerous, as long as it neither strains nor harms him.
[Imaam] Al-Bukhaari and [Imaam] Muslim [rahimahumallaah] reported from Abu Hurairah [radiyallaahu-anhu] who said: ‘’Allaah’s Messenger [sallal-laahu-alayhi-wasallam] said: ‘’If the people knew [the reward for] calling the Adhaan and standing in the first row [in congregational Salat (prayers)], and found no other way except by drawing lots, they would draw lots; and if they knew [the reward of] the Dhur prayer [in the early moments of its stated time], they would race for it [go early]; and if they knew the [reward of] Ishaa and Fajr prayers in congregation, they would come to offer them even if they had to crawl. [Sahih Al-Bukhari Book of Adhaan.’’ [Chapter: To draw lots for pronouncing the Adhaan. Hadeeth Number 615 & Sahih Muslim Number 427]
[Imaam] Al-Bukhaari and Muslim reported from Abu Hurairah [radiyallaahu-anhu] that the Messenger of Allaah [sallal-laahu-alayhi-wasallam] said: ‘’When A’dhaan is called, Satan takes to his heels and passes wind with noise during his flight in order not to hear the A’dhaan. When the A’dhaan is completed he comes back, and again take to his heels when the Iqaamah is called; and after its completion he returns again till he whispers into the heart of the person [to divert his attention from his prayer] and makes him remember things which he does not recall to his mind before the prayer and that causes him to forget how much he has prayed.’’ [Sahih al-Bukhaari Book of Adhaan. Chapter: Superiority of the Adhaan. Hadeeth Number 608]
The hadeeth shows that the A’dhaan repels the shaytaan, and that when he hears it he runs away in terror in order not to hear it. And when the A’dhaan finishes he comes back to whisper to the performer of the prayer in order to ruin his prayer. The texts showing the virtues of the A’dhaan are many.
What Should Muslim Do When the Adhaan Is Heard? When a Muslim hears the call [i.e. the A’dhaan] it is recommended that he says the same as uttered by the Mu’adh-dhin. It is reported in Saheeh Muslim from Umar Ibnul Khattaab [radiyallaahu-anhu] who said: ‘’The Messenger of Allaah [sallal-laahu-alayhi-wasallam] said, ‘When the Mu’adh-dhin says: ‘Allaah is the Greatest, Allaah is the Greatest’, then you should say: ‘Allaah is the Greatest, Allaah is the Greatest’; (and when the Mu’adh-dhin) says: ‘I testify that there is no god worthy of worship except Allaah’, you should say: ‘I testify that there is no god worthy of worship except Allaah’; and when he says: ‘I testify that Muhammad is the Messenger of Allaah’, you should say: ‘I testify that Muhammad is Allah’s Messenger.’ When he (the Mu’adh-dhin) says: ‘Hayya Alas Salaah- Come to prayer’, you should say: ‘[لَا حَوْلَ وَلَا قُوَّةَ إِلَّا بِاللهِ – There is no might and no power except with Allaah].’ When he (the Mu’adh-dhin) says: ‘[Hayya Alal Falaah- Come to success]’, you should say: ‘[لَا حَوْلَ وَلَا قُوَّةَ إِلَّا بِاللهِ -There is no might and no power except with Allaah]’; and when he (the Mu’adh-dhin) says: ‘Allah is the Greatest, Allaah is the Greatest’, then you should say: ‘Allaah is the Greatest, Allah is the Greatest.’ When he (the Mu’adh-dhin) says: ‘There is no god worthy of worship except Allaah’, and he (i.e. the person) says ‘There is no god worthy of worship except Allaah’ (sincerely) from his heart, he will enter Paradise.’’’ [Sahih Muslim Number 385]
In this, there is virtue related to [the deed of the one who] listens the A’dhaan and to repeat its words as the Mu’adh-dhin utters them – saying the same as he says in all the statements, except when he says Hayya Alas Salaah and Hayya Alal Falaah, for one should then say: [لَا حَوْلَ وَلَا قُوَّةَ إِلَّا بِاللهِ ]. That is because the statement of the Mu’adh-dhin “Hayya alas Salaah” is a call for the people to come and perform the prayer and his statement “Hayyaa Alal Falaah” is a call for them to come and receive its reward. So when a Muslim says: [لَا حَوْلَ وَلَا قُوَّةَ إِلَّا بِاللهِ ] after hearing the Mu’adh-dhin say “Hayyaa Alas Salaah and Hayyaa Alal Falaah”, he is seeking aid and assistance from Allaah to enable him to [perform the prayer and receive its reward]. And regarding the statement: ‘’Sincerely from his heart’’; this is proof that sincerity is a condition to be fulfilled because it is a basis by way of which deeds and statements [related to worship] are accepted.
Supplication After the Mu’adh-dhin finishes The Adhaan
Imaam Al Bukhaari reported from Jaabir Bin Abdillaah [radiyallaahu-anhumaa] that the Messenger of Allaah [sallal laahu alayhi wasallam] said: Whoever after listening to the Adhaan says: [اللَّهُمَّ رَبَّ هَذِهِ الدَّعْوَةِ التَّامَّةِ، وَالصَّلَاةِ الْقَائِمَةِ، آتِ مُحَمَّداً الْوَسِيلَةَ وَالْفَضِيلَةَ، وَابْعَثْهُ مَقَاماً مَحْمُوداً الَّذِي وَعَدْتَهُ – O Allaah! Lord of this perfect call (i.e. this call regarding not to ascribe partners to You) and of the regular prayer which is going to be established!] Kindly give Muhammad (sallal-laahu-alayhi-wasallam) Al-Waseelah (highest position in Paradise) and [Al-Fadhilah (extra degree of honour) and raise him to Maqam Mahmud (a station of praise and glory, i.e. the honour of intercession on the Day of Resurrection) which You have promised him], then intercession for me will be permitted for him on the Day Resurrection]. [Sahih Al-Bukhaari Book of Adhaan. Chapter: Invocation at the time of Adnaan. Hadeeth Number 614]
[Source: An Excerpt from ( فقه الأدعية والأذكار ) –pages 126- 130. Sections 3 & 4 Publisher: Daar Kunooz. 1st Ed 1426 AH (Year 2005) slightly paraphrased]