What is required of him if he leaves one of the obligatory acts of prayer, and what is the criterion for the obligatory acts of prayer?

The questioner : If he leaves an obligatory act of the salam, he makes up for it with the prostration of forgetfulness. Yes. And before the salam. What is the criterion for the obligatory acts? I mean, some things like "Subhan Rabbi al-Azim" and "Subhan Rabbi al-A'la"; in some schools of jurisprudence, the recommended acts are accepted.

The Shaykh : All right.

The questioner : I did not want to.

The Shaykh : The schools of jurisprudence differ on this. But if you hold the view that it is obligatory, then the prostration is obligatory; and if you hold the view that it is recommended, then the prostration is recommended. For example, those who say that the takbirs of transition are not obligatory but are a sunnah (recommended practice): if one leaves one of them, we say it is recommended for you to prostrate, but it is not obligatory. And according to the view that they are obligatory, we say you must prostrate.