His statement: “After these two, in the adhān for Fajr, he says twice: ‘Prayer is better than sleep,’” means that after the two ḥay‘alahs—that is, after the two calls, “Come to prayer” and “Come to success”—he says twice in the adhān for Fajr: “Prayer is better than sleep.”
His words, “Prayer is better than sleep,” consist of a subject and predicate. The scholars did not mention that both the nominative and accusative forms are permissible here, as they said regarding “Prayer is about to commence” in the prayer for an eclipse.
His words, “twice,” mean that he repeats it twice. The scholars did not mention whether he should turn right and left, or remain facing the qiblah. The basic principle is that when turning is not mentioned, he remains facing the qiblah. This statement is called tathwīb, from thāba, meaning “to return,” because the caller to prayer returns to calling people to the prayer by mentioning its virtue.
His words, “in the adhān for Fajr”: “adhān” is in a possessive construction with “Fajr,” either by attributing something to its cause—that is, the adhān whose cause is the rising of dawn—or by attributing something to its type—that is, the adhān of Fajr. The adhān for Fajr is the adhān given after the break of dawn. It is singled out for tathwīb because many people at that time are asleep or longing for sleep.
Some people in this age have mistakenly imagined that the adhān in which these two words are said is the adhān before dawn. Their argument is that one wording of the hadith states: “When you give the first adhān for the Fajr prayer, say: ‘Prayer is better…”