This is a sound (ḥasan) and singular (gharīb) narration. It clearly shows that Abū Maslama Saʿīd ibn Yazīd was asking Anas about the five obligatory prayers: when the Prophet ﷺ began—meaning, when he first entered the state of prayer—did he open with the opening supplication (duʿāʾ al-istiftāḥ), with the formula of seeking refuge (istiʿādhah), or with “All praise belongs to Allah, Lord of the worlds”?
He answered that he retained no specific knowledge on that point.
As for whether the basmalah (1) was recited aloud or silently, it has been rigorously authenticated in the report of Qatādah and others, from Anas, that the Prophet ﷺ, Abū Bakr, and ʿUmar used not to raise their voices with “In the name of Allah, the All-Merciful, the Compassionate.” (2)
Among those who narrated from al-Ḥāzimī were: the Qurʾān-reciter Taqī al-Dīn Ibn Bāsūwayh (3) of Wāsiṭ, the jurist ʿAbd al-Khāliq al-Nashtabarī (4), and Jalāl al-Dīn ʿAbd Allāh ibn al-Ḥasan.
(1) Al-Dhahabi produced an abridgement of a treatise on this question written by the hadith master Abu Bakr Ahmad b. Ali b. Thabit, better known as al-Khatib al-Baghdadi (d. 463 AH/1071 CE). He entitled his epitome Dhikr al-jahr bi-l-basmala mukhtasaran (A Concise Note on Reciting the basmala Aloud). A manuscript copy survives in the Zahiriyya Library, Damascus, miscellany no. 55; cf. al-Dhahabi wa-manhajuhu, p. 226.
(2) Shuayb notes that al-Bukhari, 2/188 (Description of the Prayer, “What is said after the opening takbir”), records the report with the wording: “The Prophet ﷺ, Abu Bakr and ʿUmar used to open the prayer with ‘al-hamdu li-llah.’” Al-Tirmidhi (no. 246) transmits it with “the recitation” in place of “the prayer” and adds ʿUthman. Muslim (no. 399) has: “I prayed with the Messenger of Allah ﷺ, Abu Bakr, ʿUmar and ʿUthman, and did not hear any of them recite bismillahi r-rahmani r-rahim.” The hadith is also reported by Ahmad, 3/264; al-Tahawi, 1/119; and al-Daraqutni, p. 119, with the explanatory gloss: “They did not pronounce bismillahi r-rahmani r-rahim aloud.” Ibn Hibban includes it in his Sahih, adding: “and they recited al-hamdu li-llahi rabbi l-ʿalamin aloud.” Another wording in al-Nasaʾi, 2/135, and Ibn Hibban reads: “I did not hear any of them pronounce bismillahi r-rahmani r-rahim aloud.” Abu Yaʿla (Musnad) preserves: “They used to begin the recitation in the audible prayers with al-hamdu li-llahi rabbi l-ʿalamin.” A further version in al-Tabarani (Muʿjam), Abu Nuʿaym (Hilya), Ibn Khuzayma (Sahih, no. 498) and al-Tahawi, 1/119, states: “and they would recite bismillahi r-rahmani r-rahim silently.” All the transmitters in these isnads are trustworthy and are cited in the two Sahihs.
(3) In al-Subki’s Tabaqat, 7/13, the word appears as “Masawiyya,” a scribal error.
(4) The name is linked to Nashtabri; Yaqut explains that it is spelled with a short “a” on the first letter, followed by a silent consonant, then a ta with two dots above, and a ba…