he rises to offer any prayer, he performs ablution; but what establishes that he must perform ablution when he rises to offer it on another day?”

The answer is: On that second day, he is again rising to pray. He is commanded to perform ablution whenever he rises to offer anything designated as prayer. Thus, whenever this occurs, the command to perform ablution applies, and ablution is obligatory for him.

This is like the words of Allah Most High:

“Establish prayer at the decline of the sun.”

What is meant is the sun’s decline as a recurring event, for which he is commanded to establish prayer.

Likewise, His words:

“Glorify your Lord with praise before sunrise and before sunset.”

This encompasses every sunrise and sunset; it does not mean a single sunrise. It is as though He said: “Before every sunrise and before every sunset; establish prayer whenever the sun declines, and rise to offer every prayer having performed ablution for it.”

Scholars have differed over whether an unrestricted command entails repetition. There are three positions within the school of Ahmad and elsewhere.

One holds that it entails repetition. This is the view of a group that includes al-Qādī Abū Yaʿlā and Ibn ʿAqīl.

Another holds that it does not entail repetition. This is the view of many, including Abū al-Khattāb.

The third holds that, if the command is tied to a cause, it entails repetition. This is the position explicitly stated by Ahmad, as in the verses concerning purification and prayer.