On this point al-Ḥāfiẓ states in Nukhbat al-Fikar: “An additional wording is acceptable so long as it does not contradict the report of someone more reliable. If it does and the opposing version is stronger, the stronger, well-preserved wording is adopted, while the conflicting one is deemed anomalous (shādh).”

I say: That condition is absent here. Even though Ḥammād ibn Salamah is among the narrators found in Ṣaḥīḥ Muslim, he is unquestionably below Shuʿbah in precision. A glance at their biographical entries in the scholars’ reference works makes this plain. Al-Dhahabī lists the first in al-Mīzān—a book reserved for narrators about whom criticism has been voiced—and describes him as “reliable, yet prone to mistakes,” whereas Shuʿbah is not mentioned there at all. The contrast becomes even clearer if you read Ibn Ḥajar’s brief biographical dictionary al-Taqrīb, where he writes: “Ḥammād ibn Salamah, reliable, devout, the most accurate transmitter from Thābit; his memory deteriorated at the end of his life,” and then: “Shuʿbah ibn al-Ḥajjāj, reliable, a meticulous ḥāfiẓ. Al-Thawrī used to say, ‘He is the Commander of the Faithful in ḥadith.’ He was the first in Iraq to scrutinize narrators, to defend the Sunnah, and he was a man of worship.”

Once this is clear, you will recognize that Ḥammād’s disagreement with Shuʿbah in this ḥadith and his extra clause cannot be accepted, for it conflicts with someone more reliable than he is; accordingly the addition is anomalous, exactly as al-Ḥāfiẓ’s statement in Nukhbat al-Fikar indicates. It is quite possible that Ḥammād narrated the report after his memory had declined and therefore slipped into error.

Imām Aḥmad seems to have hinted at the anomalous nature of this clause. He recorded the ḥadith through the route of Muʾammal—namely, Ibn Ismāʿīl—from Ḥammād immediately after the route of Shuʿbah just cited, yet he did not reproduce Ḥammād’s wording; instead he referred the reader back to Shuʿbah’s text, writing, “and he mentioned the ḥadith.” It may be that Muʾammal’s transmission from Ḥammād did not contain the disputed clause, and for that reason Imām Aḥmad made no mention of it—precisely as the ḥuffāẓ customarily do when they merely cross-reference a narration.