Acts 8:30-31

Description: Philip asks the Ethiopian eunuch if he understands Isaiah; the eunuch replies 'How can I, unless someone teaches me?'

Pope Clement VIII, Jerome's Prefaces, On Worship

II. JEROME TO PAULINUS. — Jerome cites the Ethiopian eunuch as proof that Scripture requires a guide to be understood
"'Do you think you understand what you are reading?' answered: 'How can I, unless someone teaches me?'"