The Bible was composed over a period of more than one thousand years. The human authors involved in its composition varied greatly in their background, education, social and cultural insights, and even, to an extent, in their religious perspective. Moreover, they were frequently unaware of what other inspired authors were saying or, especially, of what would be said later on. For example, there is no evidence that Hosea knew what Amos was saying, even though they prophesied in the same general period, nor were Matthew and Luke, apparently, aware of each other’s gospel.
Nevertheless, the if the Bible is the Word of God, that is, if God is in some way responsible for every part of this Book, then there must be a basic unity in these of different writings. Even though he did not dictate every word to the human authors, but allowed them to exercise their talents freely, we cannot imagine that he would allow blatant contradictions in their picture of him. This must be understood correctly. There will be differing pictures of God, but not conflicting pictures of God. Isaiah presents God as a thrice-holy king enveloped in incense smoke and surrounded by adoring seraphim (Is 6, 1-4). Jeremiah, on the other hand, sees him as one who knows the prophet from his conception and who touches the young man’s mouth with his hand in order to indicate his ability to speak the divine words (Jer 1, 1-9). Both are true pictures. God is both holy and loving, both uncontaminated by creation and yet altogether concerned with his creatures.
Also, there is a noticeable development in the picture of God from the beginning of biblical revelation to the end. There are, for example, more references to God’s anger and to his punishment of sinners in the Old Testament than there are in the New Testament. Some in the past have seen these differences as so radical that they rejected the God of the Old Testament. But differences are to be expected. God allowed Israel and the early Church to grow in their understanding and appreciation of the God who had revealed himself to them. The author of Hebrews put it most succinctly when he wrote: ‘‘In times past, God spoke in fragmentary and varied ways to our fathers through the prophets; in this, the final age, he has spoken to us through his Son” (Heb 1, 1-2)
If, then, there is a unity in the Bible by reason of its one divine author, what is that unity? The most basic source of unity and the one unifying theme of biblical revelation is, not surprisingly, the one God himself. It is the very same God who reveals himself in so many richly divergent was on every page of the Scriptures. The God of Abraham and Moses and David is the God of Jesus of Nazareth. The God of Israel is the God of Christianity. There are different ways of presenting him by reason of the different experiences of the biblical authors, but he his the one and same God.
Although not always directly expressed in so many words, every page of the inspired text tells us in some way about God’s will for salvation, for a fullness of life for his people and indeed for all of creation. As Christians, we see this divine will for salvation fully made clear in God’s Son, Jesus Christ. That is why Paul could imply that this will for salvation of Christ was present form the very beginning of creation. (Col 1, 15-20). That, again is why the author of Ephesians speaks of a mystery, or divine plan, that God had from the beginning, but which he only gradually revealed until the fullness of time when he revealed his Son (Eph 1, 3-6; 3, 2-6). Because of this underlying and unifying theme of a mystery or divine plan, scholars have frequently referred to the Bible as the record of “salvation history”.
When we understand the Bible’s unity in this way, then it is obvious that we must be acquainted with as much of the Bible as possible if we are to know what God is telling us about himself. While we recognize that the earlier parts of the Bible, including the earlier parts of the New Testament, are not the fully developed picture of the self-revealing God, they are important for understanding that picture, since they are part of the one Bible. This does not mean every verse of Scripture is of equal importance in the understanding of god and his will. It does mean, in the light of the Bible’s unity, that every verse has some importance.