Referent of the pronoun: In the word "qala" (he said) the pronoun refers to "Muhammad", and he is Muhammad bin Sirin, while in the word "laqiya" (he met) the pronoun refers to "Abu Hurayrah" (may Allah be pleased with him).

Grading: This report possibly merits being graded hasan, "in sha' Allah".
Defect and verification: This chain is "da'if" (weak) because of the weakness of al-Khidr bin Aban al-Hashimi. However, Sa'id bin Muhammad bin Thawab al-Basri corroborated him; a group narrated from him (Sa'id) and no criticism or commendation of him is reported. Yet the two of them were contradicted by someone more "thiqah" (trustworthy) and more eminent than them, namely Imam al-Hafiz Yahya bin Yahya al-Naysaburi. He narrated it from Azhar bin Sa'd al-Samman, from Ibn 'Awn ('Abdullah bin 'Awn bin Artaban), from 'Umayr bin Ishaq, from Abu Hurayrah. So he mentioned "'Umayr bin Ishaq" (in the chain) in place of Muhammad (apparently Ibn Sirin). Likewise a group of the huffaz narrated it from Ibn 'Awn, and all of them mention the name of 'Umayr bin Ishaq in place of Muhammad. That is why al-Daraqutni said in "al-'Ilal" (1852): It (the version with 'Umayr) is closer to being correct.

Technical note / Preponderance: We say: Hammad bin Salamah also narrated it from Ibn 'Awn, but there is disagreement over him. Abu Salamah Musa bin Isma'il al-Tabudhaki, Rawh bin Aslam and Ibrahim bin al-Hajjaj narrated it from Hammad and mentioned "Muhammad" (in the chain), whereas Adam bin Abi Iyas and Hajjaj bin Minhal narrated it from Hammad and mentioned "Abu Muhammad" in it, and this (Abu Muhammad) is in fact the kunyah of 'Umayr bin Ishaq, as al-Bayhaqi (2/ 232) said. So this is definitely correct, because it agrees with the narration of the other huffaz who narrate from Ibn 'Awn. And once this is established (that the narrator is 'Umayr), the hadith of 'Umayr bin Ishaq falls, in sha' Allah, into the category of "hasan".

Reference / Source: Ibn Shahin narrated it in the fifth part of "al-Afrad" (38), and al-Khatib in "Tarikh Baghdad" (10/ 135), by way of Sa'id bin Muhammad bin Thawab, from Azhar bin Sa'd, with this chain.

Reference / Source: Al-Bayhaqi narrated it in "al-Sunan al-Kubra" (2/ 232) by way of Yahya bin Yahya al-Naysaburi, from Azhar al-Samman, from Ibn 'Awn, from 'Umayr bin Ishaq, from Abu Hurayrah.

Reference / Sources: Imam Ahmad narrated it in (12/ 7462) and (16/ 10398) from Muhammad bin Abi 'Adi, and in (15/ 9510) and (16/ 10326) from Isma'il Ibn 'Ulayyah. And Ibn Hibban narrated it in (5593) and (6965) by way of Sharik bin 'Abdullah al-Nakha'i. All three of them (Ibn Abi 'Adi, Isma'il and Sharik) narrate it from 'Abdullah bin 'Awn, from 'Umayr bin Ishaq, from Abu Hurayrah.

Details of the narration: Likewise another group of the huffaz narrated it from Ibn 'Awn, whom al-Daraqutni mentioned in "al-'Ilal"; among them are Ibn al-Mubarak and Abu 'Asim al-Nabil.