Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) reports: The Prophet (peace and blessings be upon him) placed his blessed hand on my shoulder (the narrator is unsure, or perhaps the words are:) on my shoulder (this doubt is from a narrator named Sa'id, i.e. the word used for 'shoulder' differs). Then the Prophet (peace and blessings be upon him) said: "O Allah! Grant him understanding of the religion and grant him knowledge of interpretation."
(Allamah al-Haythami says:) I say: This report is mentioned in the Sahih, but without these words: "and grant him knowledge of interpretation!" Ahmad and al-Tabarani recorded it with various chains, and al-Bazzar and al-Tabarani recorded it in these words: "O Allah! Grant him knowledge of the interpretation of the Qur'an!" Ahmad's report has two routes, and the narrators of both are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب المناقب / 15515