The Messenger’s saying, “Do not recite except from the Book of al-Fatihah,” is a prohibition?

Question : The Messenger (peace and blessings be upon him), when he prayed the Fajr prayer, said, “Do not recite except al-Fatihah from the Book.” So we do not say, Shaykh, that the command following the prohibition indicates recommendation? No, no.

Answer : No, no. The fact that he excluded it from the prohibition indicates that it is obligatory, because a forbidden thing is not made permissible except by what is obligatory.