with a single salām, and by that he has discharged what is obligatory. Ibn al-Qāsim, however, holds that all the takbīrs said for bowing and for prostration are themselves obligatory, although he grants a concession for omitting one or two of those takbīrs. We have set out the rationale for this opinion in our book al-Tamhīd. In our view, nothing in the prayer is strictly obligatory except the intention, the opening takbīr, the recitation of the Mother of the Quran—Sūrat al-Fātiḥah—in every rakʿah, the standing, the bowing and the prostration as we have described, the final sitting, the salām, and the proper sequence whereby prostration follows bowing. Moreover, a rakʿah is not deemed valid unless it contains both of its prostrations.