—may Allah bless him and grant him peace—:

“A man’s prayer is not valid until he straightens his back in bowing and prostration.”

It was narrated by the compilers of the four Sunan collections. Al-Tirmidhī said: “A sound and authentic hadith.”

This explicitly states that prayer is not valid until a man returns upright after bowing and sits erect after prostration. It thus establishes the obligation to return upright as part of bowing and prostration. Although this question is distinct from that of stillness in prayer, it is closely related to it and inseparable from it.

This hadith explicitly establishes the obligation to return upright. If returning upright is obligatory to complete bowing and prostration, then remaining still in them is all the more obligatory.

His words, “straightens his back in bowing and prostration,” mean when he raises his head from them, for straightening the back is part of completing bowing and prostration. Bowing extends from the moment a person bends down until he returns upright, and prostration extends from the moment he lowers himself from standing or sitting until he returns upright. Lowering and rising are thus the two ends of bowing and prostration, completing each of them. Hence he said:

“He straightens his spine in bowing and prostration.”

This is further clarified by the fact that these two acts of returning upright are obligatory just as completing bowing and prostration is obligatory. This is like his statement in the preceding hadith:

“Then he says, ‘Allah is the Greatest,’ and prostrates