Ruling 1018 — Prayer (Ṣalāh)

If a person, before bending all the way forward to the position of rukūʿ and before his body becomes still, intentionally says the dhikr of rukūʿ, his prayer is invalid unless he says the dhikr of rukūʿ again while his body is still. If he does this inadvertently, it is not necessary to say it again.