Irenaeus of Lyons, Against Heresies 3.1

We have come to know the plan of our salvation through others — through those, that is, through whom the Gospel reached us. At first the Apostles preached it publicly; later, by God's will, they handed it down to us in the Scriptures, which were to become the foundation and pillar of our faith (1 Timothy 3:15). It is not right to claim that they preached before they possessed full knowledge, as certain people dare to assert, boasting that they are correctors of the Apostles. For after the Lord Jesus rose from the dead, and they were clothed with power from on high when the Holy Spirit came upon them (Luke 24:49; Acts 1:8), they were filled with all things and attained perfect knowledge. They went out to the ends of the earth, proclaiming the good things that come to us from God and announcing heavenly peace to humanity (Luke 2:14; Acts 10:36), each of them equally possessing the Gospel of God. Accordingly, Matthew composed a written Gospel in the Hebrew language while Peter and Paul were evangelizing in Rome and founding the Church. After their departure, Mark, the disciple and interpreter of Peter, handed down in writing what Peter had proclaimed. Luke, a follower of Paul, set down in a book the Gospel that Paul preached. Afterwards, John, the disciple of the Lord who had leaned on His breast (John 13:23), published his Gospel while living in Ephesus in Asia. All these witnesses proclaimed to us one God, the Maker of heaven and earth, announced by the Law and the Prophets, and one Christ, the Son of God. If anyone refuses to assent to them, he despises the Lord's own associates, he despises Christ the Lord, he despises the Father, and he condemns himself by resisting and opposing his own salvation — which is exactly what all heretics do (John 15:23; 1 John 2:22-23).