Answered by Shaykh Faraz Rabbani
As an imam, if one forgets to recite ‘sami Allahu liman hamida’ aloud, is sajda sahw binding upon him?
Answer:
Walaikum assalam,
Saying the dhikrs of the prayer is a confirmed sunna. Forgetfulness prostrations are necessary (wajib) only when a necessary action of the actions of the prayer is omitted forgetfully. [Durr al-Mukhtar]
See: (http://www.SunniPath.com) and Related answers.
Wassalam,
Faraz
