1 Corinthians 15:11

Therefore whether it were I or they, so we preach, and so ye believed The word preach(derived from the Latin praedicare, to proclaim) has now acquired the conventional sense of discoursing publicly about religion. The word used by St Paul refers to the work of a herald, the formal proclamation of matters of importance by one who was commissioned to make it. The substantial identity of the message, by whomsoever it was at first delivered, is a matter of fact, as the writings of the Apostles and Evangelists plainly shew. "By his earnestness in saying this, the Apostle testifies to the immense value and importance of historical Christianity." Robertson.