Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
suyuti:1083a –

"The Messenger of Allah said: 'When the Mu'adh-dhin calls the Adhan, say as he says.'" (Using translation from Ibn Mājah 718)   

السيوطي:١٠٨٣a –

"إذا أذَّن المؤذِّن فقولوا مثلَ قولهِ".  

[هـ] ابن ماجة عن أبي هريرة

See similar narrations below:

Collected by Ibn Mājah, Aḥmad, Suyūṭī
ibnmajah:718 – Abū Isḥāq al-Shāfiʿī Ibrāhīm b. Muḥammad b. al-ʿAbbās > ʿAbdullāh b. Rajāʾ al-Makkī > ʿAbbād b. Isḥāq > Ibn Shihāb > Saʿīd b. al-Musayyab > Abū Hurayrah

"The Messenger of Allah said: 'When the Mu'adh-dhin calls the Adhan, say as he says.'"  

ابن ماجة:٧١٨ – حَدَّثَنَا أَبُو إِسْحَاقَ الشَّافِعِيُّ إِبْرَاهِيمُ بْنُ مُحَمَّدِ بْنِ الْعَبَّاسِ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ رَجَاءٍ الْمَكِّيُّ عَنْ عَبَّادِ بْنِ إِسْحَاقَ عَنِ ابْنِ شِهَابٍ عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ عَنْ أَبِي هُرَيْرَةَ قَالَ

قَالَ رَسُولُ اللَّهِ ﷺ إِذَا أَذَّنَ الْمُؤَذِّنُ فَقُولُوا مِثْلَ قَوْلِهِ  

ahmad:16922 – Yaḥyá b. Isḥāq > Ḥammād b. Salamah > ʿĀṣim Ibn Bahdalah > Abū Ṣāliḥ > Muʿāwiyah b. Abū Sufyān

[Machine] I heard the Prophet ﷺ saying, "When the Mu'adhin calls the Adhan, say what he says."  

أحمد:١٦٩٢٢ – حَدَّثَنَا يَحْيَى بْنُ إِسْحَاقَ حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ عَنْ عَاصِمِ ابْنِ بَهْدَلَةَ عَنْ أَبِي صَالِحٍ عَنْ مُعَاوِيَةَ بْنِ أَبِي سُفْيَانَ

سَمِعْتُ النَّبِيَّ ﷺ إِذَا أَذَّنَ الْمُؤَذِّنُقَالَ مِثْلَ مَا يَقُولُ