al-Ghifari, who said: The Messenger of Allah (peace and blessings be upon him) said this, with the addition, “and Christians.”
I say: This chain of transmission is authentic; its narrators are reliable and are among the narrators of the two Sahihs, except that al-Bukhari narrated from ‘Abd al-Hamid ibn Ja‘far only in a suspended citation. However, I consider the mention of “Christians” in this hadith to be an error, perhaps introduced by one of the copyists. Imam Ahmad narrated it in al-Musnad (6/398), through al-Fasawi’s chain, without this wording. Its text is as follows: He said: One day he said to them, “I am setting out to the Jews. Whoever goes with me, if they greet you, then say: ‘And upon you.’” He added: “So we set out, and when we came to them, they greeted us, and we said: ‘And upon you.’”
Al-Tabarani likewise narrated it in al-Kabir (2/311/2162): Abu Muslim al-Kashshi narrated to us: Abu ‘Asim narrated to us through the same chain. Muhammad ibn Ishaq followed him in narrating it from Yazid ibn Abi Habib through the same chain. It was recorded by Ahmad, al-Tabarani, al-Bukhari in al-Adab al-Mufrad (1102), Ibn Abi Shaybah in al-Musannaf (8/630), and likewise Ibn Majah (3743—al-A‘zami’s edition), but they attributed it to Abu ‘Abd al-Rahman al-Juhani. In my view, this is anomalous and one of Ibn Ishaq’s errors. Al-Busiri deemed it defective in al-Zawa’id (223/1) on account of Ibn Ishaq’s concealment in transmission, overlooking the fact that Ibn Ishaq explicitly used a direct-transmission formula in one of Ahmad’s versions (4/233), despite having attributed it to him! Thus, the defect is the anomaly I have mentioned: it conflicts with the narration of Abu ‘Asim—al-Dahhak ibn Makhlad al-Nabil—from ‘Abd al-Hamid ibn Ja‘far. Waki‘ also followed him in narrating it from ‘Abd al-Hamid. It was recorded by Ahmad and Ibn Abi Shaybah.