It is a ḥasan report transmitted by the compilers of the Sunan and others, as noted earlier under the second type of the adhān. The wording cited by al-Nasāʾī is as follows:
Hadith Three – narrated by Anas ibn Mālik (may Allah be pleased with him), and it reaches us from him through several lines of transmission:
1 – Via Abū Qilāba from Anas, who said (1): “Bilāl was instructed to recite the adhān in doubled phrases and to make the iqāma single.”
The hadith is recorded by al-Bukhārī, Muslim, Abū Dāwūd, al-Nasāʾī, al-Tirmidhī, al-Dārimī, Ibn Mājah, al-Ṭaḥāwī, al-Dāraqutnī, al-Ḥākim, al-Ṭayālisī, Aḥmad, and al-Khaṭīb. Some relate it through Khālid al-Ḥadhdhāʾ, others through Ayyūb; both routes go back to Abū Qilāba.
The version reported by al-Nasāʾī and al-Ḥākim through Ayyūb reads: “The Messenger of Allah ﷺ instructed Bilāl….” Al-Dāraqutnī also transmits this wording from al-Nasāʾī. Al-Ḥākim commented, “Authentic according to the criteria of the two Shaykhs, though they did not include it with this exact wording.”
Ayyūb additionally ends the narration with the phrase “except the iqāma,” and this wording appears in both Ṣaḥīḥs and elsewhere.