St. Irenaeus, Against the Heresies, III

The Lord of all gave to His apostles the power of the gospel, and
by them we also have learned the truth, that is, the teaching of
the Son of God – as the Lord said to them, `He who hears you hears
Me, and he who despises you despises Me, and Him Who sent Me’
[Lk.10:16]. For we learned the plan of our salvation from no other
than from those through whom the gospel came to us. The first
preached it abroad, and then later by the will of God handed it
down to us in Scriptures, to be the foundation and pillar of our
faith. For it is not right to say that they preached before they
had come to perfect knowledge, as some dare to say, boasting that
they are the correctors of the apostles. For after our Lord had
risen from the dead, and they were clothed with the power from on
high when the Holy Spirit came upon them, they were filled with
all things and had perfect knowledge. They went out to the ends of
the earth, preaching the good things that come to us from God, and
proclaiming peace from heaven to all men, all and each of them
equally being in possession of the gospel of God.