The Prophet ﷺ called out, "Abu Dharr."I replied, "At your service and pleasure, Messenger of Allah, may I be your ransom."
حدثنا موسى بن إسمعيل حدثنا حماد ح و حدثنا مسلم حدثنا هشام عن حماد يعنيان ابن أبي سليمان عن زيد بن وهب
قال النبي ﷺ يا أبا ذر فقلت لبيك وسعديك يا رسول الله وأنا فداؤك
[Hasan] Bayhaqi reported it in Shuab al-Iman, no. 8890, from the hadith of Abu Dawud through the same chain.Hisham is Dastawai and Hammad is Ibn Salama, and both of them narrated it from Hammad bin Abu Sulayman, and he narrated this before his memory became confused. See Majma al-Zawaid 1/119, 120.Its basis is agreed upon, Bukhari, no. 6268, and Muslim, no. 94 after 991, from the hadith of Zayd bin Wahb through the same chain, at length.