Biblical Authors Cite Sources in Their Writings
Sometimes we think of the Bible as if it were a book that fell from heaven to earth. But, while the Bible is inspired by the Holy Spirit, regular humans (who were prophets) wrote it. And they cited sources in their writings in similar ways that we do. Once we realize this, it helps us to read the Bible in the way that God and its authors intended it to be read. The Bible is both historical and theological. Authors wrote books of the Bible within real historical times, and God inspired it to speak beyond those events in history. Let's take a look at the Bible itself to explain how this worked.
The Old Testament
The Book of Kings specifies numerous written sources that it informed its narrative:
1 Kings 11:41: Now the rest of the acts of Solomon, and all that he did, and his wisdom, are they not written in the Book of the Acts of Solomon?
1 Kings 14:19: Now the rest of the acts of Jeroboam, how he warred and how he reigned, behold, they are written in the Book of the Chronicles of the Kings of Israel.
1 Kings 14:29: Now the rest of the acts of Rehoboam and all that he did, are they not written in the Book of the Chronicles of the Kings of Judah?
1 Kings 16:14: Now the rest of the acts of Elah and all that he did, are they not written in the Book of the Chronicles of the Kings of Israel?
2 Kings 1:18: Now the rest of the acts of Ahaziah that he did, are they not written in the Book of the Chronicles of the Kings of Israel?
2 Kings 14:28: Now the rest of the acts of Jeroboam and all that he did, and his might, how he fought, and how he restored Damascus and Hamath to Judah in Israel, are they not written in the Book of the Chronicles of the Kings of Israel?
2 Kings 15:21: Now the rest of the deeds of Menahem and all that he did, are they not written in the Book of the Chronicles of the Kings of Israel? (ESV)
Genesis may also attest to earlier sources by using the phrase "The generations of." For example, Genesis 5:1 reads, "This is the book of the generations of Adam" (cf. Gen 2:4; here; 6:9; 10:1; 11:10, 27; 25:12, 19; 36:1, 9; 37:2). Whatever the precise meaning of the word "generations," it likely refers to some prior record, perhaps a literary record.
The New Testament
New Testament authors also cite sources that helped them write their books. Luke provides the most detail about his writing process in Luke 1:1–3:
Inasmuch as many have undertaken to compile a narrative of the things that have been accomplished among us, just as those who from the beginning were eyewitnesses and ministers of the word have delivered them to us, it seemed good to me also, having followed. (ESV)
Jude finds wisdom in the Book of Enoch (a non-inspired but helpful book):
Enoch, the seventh from Adam, prophesied about them: “See, the Lord is coming with thousands upon thousands of his holy ones to judge everyone, and to convict all of them of all the ungodly acts they have committed in their ungodliness, and of all the defiant words ungodly sinners have spoken against him. (1:14–15 NIV)
Paul identified the magicians in Pharaoh's court as Jannes and Jambres, names not mentioned in Scripture. He writes, "Just as Jannes and Jambres opposed Moses, so these men also oppose the truth, men corrupted in mind and disqualified regarding the faith" (2 Tim 3:8 ESV). While it's unclear what source Paul used here, the names Jannes and Jambres were common designations of two magicians that opposed Moses in Paul's day.
So What Does This Mean?
It means that God used regular human beings like us to write inspired Scripture. It's a mystery almost as great as the incarnation of Lord. It also means that the Bible is a historically verifiable book. In other words, biblical authors investigated the matters that they wrote about before they wrote their works (Luke testifies of this explicitly). It shows us that our faith is not ahistorical but is rooted in real life.
So What Doesn't This Mean?
It doesn't mean the Pentateuch was spliced together by various schools of thought, some favouring the laws of the nation and others favouring the priestly code of conduct. Certainly, you can investigate the evidence to see if such an idea holds water. But, for my part, I see no conclusive evidence that the Pentateuch was composed by various idealogical schools. The Pentateuch testifies that Moses used sources ("the generations of" and direct testimony from God), but that's as far as the explicit extant evidence goes.
Final Reflection
The Bible is both a book written like any other book and a book that God divinely inspired. We should read it within its historical context but also know that God's mind is behind the whole Bible. It is both historical and theological; it testifies to diverse settings and it is unified because of the plan of God. And we can both affirm that biblical authors cited sources and God inspired it. There is no contradiction. This frees us from wrong assumptions about the Bible and allows us to read it in the way that it was intended to be read.