The Messenger of Allah ﷺ placed his hand on my shoulder, or on my upper arm — Saeed was uncertain which — and said, "Allah, grant him understanding of the religion and teach him the interpretation."
حدثنا حسن بن موسى حدثنا زهير أبو خيثمة عن عبد الله بن عثمان بن خثيم عن سعيد بن جبير
أن رسول الله ﷺ وضع يده على كتفي أو على منكبي شك سعيد ثم قال اللهم فقهه في الدين وعلمه التأويل
Its isnad is sahih. Zuhayr Abu Khaythama is Zuhayr bin Muawiya, whose kunya was Abu Khaythama. In the two original manuscripts it appears here as "Zuhayr bin Khaythama," which is an error, and there is no one among the narrators - as far as we know - who is named this. The hadith appears in Majma al-Zawaid 9:267, attributed to Ahmad and Tabarani, where it is stated, "Ahmad has two routes whose narrators are the narrators of the sahih." See 1840, 2422.