His statement: “the two tasbihs of bowing and prostration.”

The author, may Allah have mercy on him, did not explain these two tasbihs here, though he explained them earlier, when he mentioned that one says while bowing, “Glory be to my Lord, the Magnificent,” and while prostrating, “Glory be to my Lord, the Most High.” Thus, the worshipper’s saying in bowing, “Glory be to my Lord, the Magnificent,” is obligatory, and his saying in prostration, “Glory be to my Lord, the Most High,” is obligatory.

The evidence for this is that when Allah’s saying was revealed,

“So glorify the Name of your Lord, the Magnificent.” [al-Wāqiʿah]

the Prophet ﷺ said: “Use it in your bowing” (2).

This is an explanation from the Prophet ﷺ of where this tasbih is to be said. It is well known that we must refer back to the Messenger’s ﷺ explanation of the Quran, for the person most knowledgeable of Allah’s words among all creation was the Messenger of Allah ﷺ. For this reason, interpreting the Quran through the sunnah occupies the second rank. We first interpret the Quran by the Quran itself, such as:

“The Striking Calamity! What is the Striking Calamity? And what will make you know what the Striking Calamity is? The Day people will be like scattered moths.”

Thereafter, it is interpreted through the sunnah of the Messenger of Allah ﷺ, for it clarifies it—as in this verse:

“So glorify the Name of your Lord, the Magnificent.” [al-Wāqiʿah]

where the Prophet ﷺ said: “Use it in your bowing.”

This explains where this tasbih is to be said. At times, the Prophet ﷺ also explains the meaning, as in Allah’s saying:

“For those who do good is the finest reward and more besides.” [Yūnus: 26]