From the First Book of the Commentary on Matthew.
Concerning the four Gospels which alone are uncontroverted in the Church of God under heaven, I have learned by tradition that the Gospel according to Matthew, who was at one time a publican and afterwards an Apostle of Jesus Christ, was written first; and that he composed it in the Hebrew tongue and published it for the converts from Judaism. The second written was that according to Mark, who wrote it according to the instruction of Peter, who, in his General Epistle, acknowledged him as a son, saying, "The church that is in Babylon, elect together with you, saluteth you; and so doth Mark my son." 
And third, was that according to Luke, the Gospel commended by 
Paul, which he composed for the converts from the Gentiles. Last of all, that according to John.