Although God is ultimately the source of Scripture (2 Tim 3:16), He chose to use human authors as the instruments through which He set forth His written revelation. In using these men to record His Word, God did not suppress the individual personalities or writing styles of the human writers, but rather He used them to communicate precisely what He was pleased to reveal through them. The Bible, then, has a divine author and a human author.
Commonly known as the dual authorship of Scripture, this doctrine is most clearly taught in Peter’s second epistle, where the apostle describes the writing of Scripture as the process in which “men moved by the Holy Spirit spoke from God” (2 Peter 1:21b). According to Peter, human prophets spoke or wrote the Scriptures, but as they did so, they were superintended by the Holy Spirit in such a way that their very words were from God Himself.
This same understanding of dual authorship is also seen in the Gospel of Matthew, specifically where the apostle introduces quotations from the OT in Matthew 1:22 and 2:15, describing them as “what was spoken by the Lord through the prophet.” In this description, Matthew uses two prepositional phrases to modify the verb “was spoken.” According to Matthew 1:22 and 2:15, these OT prophecies were spoken “by [hupo] the Lord,” and they were spoken “through [dia] the prophet.” Both prepositions in these verses (hupo and dia) are used to indicate the personal means by which the action of the verb is accomplished, often referred to as agency. There is, however, a subtle but significant distinction between the use of these two prepositions, and this distinction makes a helpful contribution to our understanding of the dual authorship of Scripture.
In Matthew 1:22 and 2:15, the preposition hupo is used to express ultimate (or primary) agency, whereas the preposition dia is used to express intermediate (or secondary) agency. The distinction is this: the ultimate agent is the person who is ultimately responsible for the action of the verb, and the intermediate agent is the person who is used by the ultimate agent to carry out that action. In simpler terms, if A is the ultimate agent, B is the intermediate agent, and C is the action of the verb, the idea is that A uses B to perform C.
The implications of this are profound. According to Matthew 1:22 and 2:15, the person who is ultimately responsible for the action of speaking forth the Old Testament prophecies is the Lord Himself, for Matthew refers to the words of prophecy as “what was spoken by [hupo—ultimate agency] the Lord.” In addition, however, these verses also indicate that the Lord used intermediate agents to speak forth these words of prophecy, for Matthew refers to “what was spoken…through [dia—intermediate agency] the prophet.” Put very simply, A (God) used B (the prophets) to perform C (write Scripture).
In Matthew 1:22 and 2:15, then, the doctrine of dual authorship is unmistakable. Did the prophets speak forth the content of the Old Testament? Yes they did. But in doing so they served as a mouthpiece for the One who was ultimately responsible for the words recorded in Scripture. The Bible was indeed written by men, and yet it is truly the Word of God.