What is the ruling on someone who forgot the first Tashahhud, then returned to it forgetfully after reciting one verse from Al-Fatihah, then remembered and stood up? Should he intend the prostration of forgetfulness (sujud al-sahw) for merely omitting the first Tashahhud, or for omitting it and then returning to it? And should he complete Al-Fatihah or repeat it?

If a worshiper stands up from the first tashahhud forgetfully, and remembers after beginning the recitation of Al-Fatiha, it is forbidden for him to return, and his prayer becomes invalid if he was aware and deliberate.

If he returns forgetfully, then remembers the prohibition of returning, and stands for the third rak'ah, his prayer is valid, and he should perform the prostration of forgetfulness (sujood as-sahw).

If he returns after beginning the recitation of Al-Fatiha, he must restart the recitation of Al-Fatiha from the beginning.