Tertullian

They bear in mind how the churches were rebuked by the apostle: "O foolish Galatians, who hath bewitched you? " and, "Ye did run so well; who hath hindered you? " and how the epistle actually begins: "I marvel that ye are so soon removed from Him, who hath called you as His own in grace, to another gospel." That they likewise (remember), what was written to the Corinthians, that they "were yet carnal," who "required to be fed with milk," being as yet "unable to bear strong meat; " who also "thought that they knew somewhat, whereas they knew not yet anything, as they ought to know.