“but He intends to purify you and complete His favour upon you”

correspond to His words:

“and that you complete the prescribed number and glorify Allah for having guided you, and that you may be grateful.”

The point here is that Allah, Glorified is He, wills, by way of religious prescription, that we proclaim His greatness (takbīr) for having guided us. Hence some of the early Muslims, such as Zayd ibn Aslam, said that this refers to the takbīr of Eid. The Muslim community unanimously agrees that the Eid prayer is distinguished by additional takbīrs. The reference to takbīr may also encompass the Eid prayer itself, just as prayer is called glorification, standing, prostration, and Quran recitation. Similarly, the two prayers offered together are included in the remembrance of Allah in His words:

“When you depart from Arafat, remember Allah at al-Mashʿar al-Harām.”

And the sermon and prayer are meant by His words:

“Hasten to the remembrance of Allah and leave off trade.”

This would mean that, because the prayer is called takbīr, it is distinguished by additional takbīrs, just as the dawn prayer, being called Quran recitation, is distinguished by additional recitation. Its longer recitation was made a substitute for the two additional units in a four-unit prayer. Likewise, “the night prayer,” being called standing in His words:

“Stand in prayer at night,”

is distinguished by prolonged standing. Thus the Prophet, may Allah bless him and grant him peace, would prolong his standing, bowing, and prostration at night more than he did during the day.

For this reason, some of the early Muslims said that prolonging prayer at night is better, and that increasing the number of bowings and prostrations during the day