(1) I note: Abu Dawud (no. 3754) records this report in the Book of Foods, Chapter “Food Offered by Two Contestants,” through the chain: Harun b. Zayd al-Nahwi → his father → Jarir b. Hazim → al-Zubayr b. Khirrit → Ikrima → Ibn Abbas. The chain is strong, yet several scholars considered it mursal (missing Ibn Abbas). Abu Dawud himself says: “Most transmitters who narrate from Jarir omit Ibn Abbas.” Nevertheless, al-Hakim declared it sound in al-Mustadrak, 4 / 129, via Harun b. Musa al-Nahwi → al-Zubayr b. al-Harith → Ikrima → Ibn Abbas, with the wording: “The Messenger of Allah forbade eating the food of two contestants.” He graded the isnad sahih, and al-Dhahabi endorsed this in his Talkhis, although he still preferred the mursal version here and in al-Mizan. The report is further supported by a corroborating narration in Juz Ibn al-Sammak, fol. 64 / 1, from Abu Hurayra: “Two contestants are not to be answered, nor is their food to be eaten.” All its transmitters are trustworthy, which strengthens the hadith. Al-Khattabi explains that al-mutabariyan are two people who imitate each other’s action in rivalry, each trying to outdo the other. The practice is discouraged because it involves ostentation and self-aggrandizement. (2) Reports limiting the salutation at the end of prayer to a single taslimah come from Saʿd b. Abi Waqqas, ʿAisha, Anas, Sahl b. Saʿd al-Saʿidi, and Salama b. al-Akwaʿ; I documented them in my notes on Zad al-Maʿad, 1 / 259, 261, and their combined chains are authentic. Al-Shawkani states in Nayl al-Awtar, 2 / 333, that the legitimacy of one taslimah is the position of Ibn ʿUmar, Anas, Salama b. al-Akwaʿ, and ʿAisha among the Companions; al-Hasan, Ibn Sirin, and ʿUmar b. ʿAbd al-ʿAziz among the Successors; and of Malik, al-Awzaʿi, the Imamiyya, and one of the two opinions reported from al-Shafiʿi, among others.