Heinrich Bullinger discusses the truthfulness and certainty of the Word of God in the first sermon of his first Decade. There is much herein worthy of meditation.
First, I have to declare what the word of God is. Verbum in the scriptures, and according to the very property of the Hebrew tongue, is diversely taken. For it signifieth what thing soever a man will ; even as among the Germans the word ding is most largely used. In St Luke, the angel of God saith to the blessed virgin: ”With God shall no word be unpossible ;” 1 which is all one as if he had said, all things are possible to God, or to God is nothing unpossible. Verbum also signifieth a word uttered by the mouth of man. Sometime it is used for a charge, sometime for a whole sentence, or speech, or prophecy: whereof in the scriptures there are many examples. But when verbum is joined with any thing else, as in this place we call it verbum Dei, then is it not used in the same signification. For verbum Dei, “the word of God,” doth signify the virtue and power of God : it is also put for the Son of God, which is the second person in the most reverend Trinity. For that saying of the holy evangelist is evident to all men, “The word was made flesh.” But in this treatise of ours, the word of God doth properly signify the speech of God, and the revealing of God’s will ; first of all uttered in a lively-expressed voice by the mouth of Christ, the prophets and apostles ; and after that again registered in writings, which are rightly called “holy and divine scriptures.” The word doth shew the mind of him out of whom it cometh: therefore the word of God doth make declaration of God. But God of himself naturally speaketh truth; he is just, good, pure, immortal, eternal: therefore it followeth that the word of God also, which cometh out of the mouth of God, is true, just, without deceit and guile, without error or evil affection, holy, pure, good, immortal, and everlasting. For in the gospel saith the Lord, “Thy word is truth”.” And the apostle Paul saith, “The word of God is not tied.” Again, the scripture everywhere crieth : “The word of the Lord endureth for ever.” And Salomon saith: “Every word of God is purely cleansed. Add thou nothing to his words, lest peradventore he reprove thee, and thou be found a liar.” David also saith: ”The sayings of the Lord are pure sayings, even as it were silver cleansed in the fire, and seven times fined from the earth.”
This you shall more fully perceive, dearly beloved, if I speak somewhat more largely of the cause or beginning, and certainty, of the word of God. The word of God is truth: but God is the only well-spring of truth: therefore God is the beginning and cause of the word of God.