We hold communion with the apostolic churches because our doctrine is in no respect different from theirs. This is our witness of the truth.
Tertullian, c.197, 3.252-3
It is unlawful to assert that the apostles preached before they possessed "perfect knowledge," as some do even venture to say, boasting themselves as being improvers of the apostles. For after our Lord rose from the dad, the apostles were energized with power from on High when the Holy Spriit came down [upon them]. They were completely filled and had perfect knowledge. They departed to the ends of the earth, preaching the glad tidings of the good things sent to us from God.
Irenaeus, c.180, 1.414.