What is the ruling on someone who intended to bow in the first rak'ah, lowered his hands from his chest, then remembered that he had not recited a surah after Al-Fatihah, so he raised his hands again and recited it? Is sujud as-sahw (prostration of forgetfulness) required of him?

This person did well by catching himself and reciting the surah (definition) before bowing for rukūʿ, as is the view of some scholars, such as the Malikis. His prayer is valid, and he is not required to perform the prostration of forgetfulness (sajdat as-sahw), because his movement was slight.