3] 1. First [, then, we receive and embrace with our whole heart] the Prophetic and Apostolic Scriptures of the Old and New Testaments as the pure, clear fountain of Israel, which is the only true standard by which all teachers and doctrines are to be judged.
4] 2. And since of old the true Christian doctrine, in a pure, sound sense, was collected from God's Word into brief articles or chapters against the corruption of heretics, we confess, in the second place, the three Ecumenical Creeds, namely, the Apostles', the Nicene, and the Athanasian, as glorious confessions of the faith, brief, devout, and founded upon God's Word, in which all the heresies which at that time had arisen in the Christian Church are clearly and unanswerably refuted.
http://ichabodthegloryhasdeparted.blogspot.com/2012/05/formula-of-concord-comprehensive.html