There r certain chapters( Suras like surah Teen) in Holy Quran for which we have to answer. If we are r behind an Imaam (or alone) and he recites such Surah then in this case, is it necessary to answer such sura by Muqtadees or by Imaam himself...
Answer:
Source: tafsir ibn kathir: There are some surah like ‘al-ala’ in the quran where we have to respond with tasbih, here we will take example of surah ‘al-ala’ [87:1] the first verse says,” Sabbihi isma rabbika al-aAAla” (Glorify the Name of your Lord, the Most High.) And we respond it with “subhana rabiyal ala” (Glory to my Lord, the Most High.)Imam Ahmad recorded from Ibn `Abbas that whenever the Messenger of Allah would recite the first verse of the surah ‘al-ala’ he would the recite “subhana rabiyal ala” (Glory to my Lord, the Most High.)
The majority of the scholars are of the opinion that when a believer is in congregation he should not answer, (as it is recommended to listen to the recitation of quran while the imam is reciting) so that any of the fellow believers are not disturbed. However if he would like to recite in heart then there is no harm in it.
Other than the above case, the believer should recite the response, whether he be sunnah prayer, or reciting quran any where. And Allah alone knows the best.
