from a bent posture. For that would prevent his prostration from having a defined measure and limit according to his ability. If this is obligatory, then maintaining a balanced posture in bowing and between the two prostrations is also obligatory.
Furthermore, this ensures that bowing and prostration are completed fully.
Moreover, if the actions of prayer have prescribed measures, they must have a definite extent. This requires remaining still. Someone who pecks like a crow gives his action no real duration at all, for a thing’s measure and extent are something beyond its mere existence. Thus, something that continues indefinitely is said to have no measure: a measure applies not to the slightest movement, but to a movement that has some duration.
Furthermore, Allah, Mighty and Majestic, has commanded us to establish prayer. To establish something is to make it stand, and something standing is upright and balanced. The actions of prayer must therefore be steady and balanced. This can only be achieved by holding its constituent parts firmly and steadily, which entails remaining still. Someone who pecks like a crow has not properly established his prostration, nor does he complete it if he does not remain firm and settled. The same applies to someone bowing.
This is illustrated by the report in the two Sahīh collections, from Qatāda, from Anas ibn Mālik—may Allah be pleased with them both—who said: The Messenger of Allah, may Allah bless him and grant him peace, said:
“Straighten your rows, for straightening the row is part of perfecting the prayer.”
They also both narrated it on the authority of