In congregation – if the imam recites so slowly that between every ayah of the Qur’an that he recites there is a silence greater than the length it takes to recite 3 tasbihs – would such prayer be valid or would it have to be repeated?
The prayer would be makruh-e-tahriman (severely disliked) and it would be required to repeat it again.
Imam Haskafi writes, “Understand! If thinking keeps him busy for a period, in which a rukan can be done, and he hasn’t been reciting qir’aat or tasbeeh (i.e. he was quiet whilst thinking), sajda-e-sahw (prostration of forgetfulness) is wajib upon him.”
[al Durr al-Mukhtar, Page 101]
Allah knows best.
Answered by Mawlana Mohammed Kashif