How do the Old and New Testaments fit together? I would venture to suggest something like this. The OT is fundamentally and centrally characterised by expectation. It looks forward, in various ways and from different perspectives, to the decisive action of God in history which will redeem Israel. Psalm 130 captures the beating heart of the OT. Of course, this sense of expectation has its basis in remembrance. God has acted in the past, but the history of Israel is a demonstration that this past action was not decisive: it did not free Israel from sin or danger. It could only be a sign of the full and final action of God to come. The OT is basically forward looking.
By contrast, the NT is essentially about remembering. It is oriented backward, and is characterised by memory and testimony. The heart of the apostles' ministry is to pass on what they have heard and seen. The opening of 1 John is typical. Of course, the NT also looks forward to a glorious climax. But there is a sense in which the climax has already come. Nothing new is looked for or expected from God. The decisive action has been taken, and the expectation that there is is just for its completion. The NT is basically about remembering.
What conclusions can be drawn from this?
1. The Scriptures are a unity. This is not obvious, certainly not as obvious as many of us who have grown up with the Bible often assume. The unity comes from outside the text. The OT and NT are united in so far as the decisive action of God expected in the former is the same as that remembered in the latter. In other words, the Scriptures find their unity in Christ.
2. The unity of Scripture is not found in the similarity or (more strongly) the identity of the old and new covenants, but in their symmetrical relation to Jesus Christ. He is the main thing.
3. The Scriptures live by their relationship to Christ. He is the Living Word, who has life in himself, and the Bible lives from him. I would venture to suggest that the Bible only becomes life-giving when this relation is seen.
In short, to be a person of the Bible is to look beyond (better, through, or perhaps along) the Bible to the One expected and remembered there.