[al-Hijr], and His statement, Exalted is He: “When it is said to them, ‘Bow down,’ they do not bow.” [al-Mursalāt: 48] [al-Mursalāt] And His statement, Exalted is He: “Your only guardian is Allah, His Messenger, and those who believe—those who establish prayer, give alms, and bow down.” [al-Mā'ida: 55] [al-Mā'ida]

Since Allah, Glorious and Exalted is He, has prescribed bowing and prostration to Him in His Book just as He has prescribed prayer itself, the Prophet—may Allah bless him and grant him peace—is the one who explains to people what was sent down to them. His Sunnah interprets the Book, makes it clear, points to it, and expresses its meaning. When an action of his was performed in compliance with a command or as an explanation of something stated only in general terms, it bore the same ruling as that which it fulfilled and explained.

Thus, because the Prophet—may Allah bless him and grant him peace—performed one bowing and two prostrations in every unit of prayer, both were obligatory. This was his compliance with Allah’s command to bow and prostrate, and his explanation of what was mentioned only in general terms in the Quran. Likewise, recourse must be had to his Sunnah regarding the manner of prostration. He performed both obligatory and voluntary prayers, while people prayed during his lifetime, and he never prayed without straightening up from bowing and prostration and observing tranquility in all the acts of prayer. Everyone who transmitted accounts of his obligatory and voluntary prayers reported this. People prayed during his lifetime, and he never prayed without straightening up from bowing and prostration and observing tranquility. His Companions likewise prayed in this manner during his lifetime. This entails that stillness and tranquility are obligatory in these acts, just as it entails their required number: two prostrations for every bowing.

Furthermore, his constant observance of this in every prayer, every day, despite the great number of prayers, is among the strongest proofs that it is obligatory. Had it not been obligatory, he would have omitted it even once to demonstrate that doing so was permissible, or he would have stated that it was permissible to omit it. Since he did not demonstrate—either by his words or his actions—that it was permissible to omit it, but instead observed it constantly, this proves that it is obligatory.

Furthermore, it is authentically established from the Prophet—may Allah bless him and grant him peace—in Sahīh al-Bukhārī “that he said to Mālik ibn