“According to the grace of God which was given unto me, as a wise master-builder I laid a foundation,” writes Paul to the Corinthians. What was this foundation of which he speaks? It was certainly nothing peculiar to Paul, nor did it originate with him. It was something which the apostles had in common, and we must turn back briefly to the Gospels and to the words of the Lord Jesus Himself for a first definition of it. Hear Him at Caesarea Philippi, as He addresses Simon Peter in these remarkable terms: “Thou art Peter, and upon this rock I will build my church” (Matt. 16:18).