Irenaeus

But again, we allege the same against those who do not recognise Paul as an apostle: that they should either reject the other words of the Gospel which we have come to know through Luke alone, and not make use of them; or else, if they do receive all these, they must necessarily admit also that testimony concerning Paul, when he (Luke) tells us that the Lord spoke at first to him from heaven: "Saul, Saul, why persecutest thou Me? I am Jesus Christ, whom thou persecutest;" and then to Ananias, saying regarding him: "Go thy way; for he is a chosen vessel unto Me, to bear My name among the Gentiles, and kings, and the children of Israel. For I will show him, from this time, how great things he must suffer for My name's sake." Those, therefore, who do not accept of him [asa teacher], who was chosen by God for this purpose, that he might boldly bear His name, as being sent to the forementioned nations, do despise the election of God, and separate themselves from the company of the apostles. For neither can they contend that Paul was no apostle, when he was chosen for this purpose; nor can they prove Luke guilty of falsehood, when he proclaims the truth to us with all diligence.