Answered by Shaykh Faraz Rabbani
The Imam at our local masjid sometimes ‘stretches’ out the Allahu Akbar during a movement when in salat. It occurred to me that although I repeat it silently after he says it, because he stretches it out I may actually finish saying Allahu Akbar before the Imam. I was wondering, what is the ruling on such a case?
Answer:
Walaikum assalam wa rahmatullah,
This doesn’t affect the validity or soundness of prayer. But it would be more proper to give one’s takbir (saying ‘Allahu Akbar’) such that one begins and ends it after the imam.
Faraz Rabbani