In his next Q/A, Chytraeus deals with the Scripture principle as he gives the reason for certainty in Christian doctrine.1 Certainty is rooted in authority and the expression of that authority (revelation). The two are intimately connected: for spiritual authority to be binding, it must have a dixit Dominus, and we find that with certainty not in decrees or canons, but only in Scripture. Only in Holy Scripture does God reveal himself–particularly, his “secret will”–verbally. Other types of testimony (e.g., miracles), which Chytraeus treats in the next part of the answer, are logically subsequent to the conviction of Scripture’s authority, which comes under the guidance of the Holy Spirit, and only bolster and strengthen that authority; they do not prove it.
Quae est caussa certitudinis in doctrina Christiana?
Summa & praecipua caussa certitudinis est autoritas & PATEFACTIO divina, in libris Prophetarum & Apostolorum comprehensa, seu, DIXIT DOMINUS: qui veritas ipsa est, & mentiri nescit.
Huic aeternae & immotae veritati, Spiritu sancto duce assentientes, plurimum etiam sequentia Testimonia confirmant: ut certius statuant quod sola haec doctrina de DEO, in scripturis sanctis tradita, sit certa, vera, divina, & sola hominibus arcanam voluntatem Dei patefaciat.
What is the reason for certainty in Christian doctrine?
The highest and chief reason for certainty is divine authority and revelation, expressed in the books of the Prophets and Apostles, or, the dixit Dominus (“the Lord said”), who is truth itself and does not know how to lie.
Very many subsequent testimonies, too, strengthen those who assent, with the Holy Spirit as their leader, to this eternal and unshakeable truth, in order to establish more surely that this doctrine alone concerning God, handed down in the Holy Scriptures, is sure, true, divine, and alone reveals to men the secret will of God.