Tertullian

When, again, he mentioned "certain false brethren as having crept in unawares," who wished to remove the Galatians into another gospel, he himself shows that that adulteration of the gospel was not meant to transfer them to the faith of another god and christ, but rather to perpetuate the teaching of the law; because he blames them for maintaining circumcision, and observing times, and days, and months, and years, according to those Jewish ceremonies which they ought to have known were now abrogated, according to the new dispensation purposed by the Creator Himself, who of old foretold this very thing by His prophets.