The Prophet’s reply in the hadith of Abū Dharr, when he was asked, “Which words are best?” and answered, “Glory and praise be to Allah,” was given in response to a question. He may have known of some particular circumstance affecting the questioner. Likewise, when he said:

“The best words that I and the prophets before me have said are: ‘There is no deity worthy of worship except Allah’”—and so on—

he meant words of remembrance, not Quranic recitation. For reciting the Quran is, generally speaking, superior to remembrance as a category, although these words may sometimes be superior to recitation. Thus, uttering the two testimonies of faith when entering Islam, renewing one’s profession of it, or on occasions that call for them—such as after ablution, at the conclusion of prayer, in the call to prayer, and on other such occasions—is superior to recitation.

The same applies to repeating the words of the caller to prayer. If someone is reciting the Quran and hears the caller, repeating the words of the call is better for him at that moment than continuing his recitation. Indeed, it is recommended that he interrupt his recitation for this purpose, because this is the appointed time for that act of worship: its opportunity passes when its time passes, whereas the opportunity to recite remains.

We therefore say that there are three situations. In the first, saying the words quietly is recommended and raising the voice is disliked, because one is in a lowered position, as when bowing or prostrating. Here, glorifying Allah is better than declaring His oneness and proclaiming His greatness. The same applies in the bottoms of valleys.

As for situations in which the Sunnah is to raise the voice and proclaim the words openly, such as when ascending high ground or giving the call to prayer, the Sunnah is to declare Allah’s oneness and proclaim His greatness. As for situations in which both are prescribed, this may apply.