Abū Yaʿlā included it in his Musnad (284/2): Kāmil ibn Ṭalḥah narrated to us; Ḥammād ibn Salamah narrated to us, from Muḥammad ibn ʿAmr, from Abū Salamah, from Abū Hurayrah, attributed to the Prophet.

I say: This is a sound chain of transmission. All its narrators are trustworthy and well known among the narrators covered in al-Tahdhīb. There is some criticism concerning Kāmil and Ibn ʿAmr, but it is not detrimental. The hadith is an explicit text that the sunnah is to say “Allāhu akbar” and then prostrate, and that one says “Allāhu akbar” while seated and then rises. Thus, it refutes what some blind followers do when they prolong the takbīr from sitting until standing.