A regular blog reader writes to me, disturbed by what he takes to be a disunity in Scripture. It seems to him that the God of the Old Testament is judgmental and wrathful, and that the God of the New Testament is merciful and forgiving - they are two Gods, not one. God the Father bad cop; God the Son good cop. (Worse than that, my reader has the impression that Jesus was "nice" - as if being "nice" is something Jesus ever really was.)
But this dichotomy is fundamentally wrong, and it's the kind of mistake you can fall into only if you have a cursory familiarity with Scripture, and if you believe the shorthand notes of others who have only a cursory familiarity with Scripture.
Take the Old Testament book of Isaiah alone, as an example at random. Every time God speaks through Isaiah and proclaims woes and punishments for His people, He counters with hope and forgiveness. Mercy is not peculiar to the New Testament. I can think of no example of any OT book that reveals only God's wrath and punishment without revealing a more profound measure of blessing and contentment at the other end of the suffering. A peculiar and profound and ineffable joy always follows the expression of God's "anger", given to those who turn back to Him and have faith in Him - even after they've abandoned Him and betrayed Him.
Beyond that, there are the odd mysteries left hanging and tantalizing in the OT, and fulfilled only fully in the NT. Melchizedek is one - a figure utterly baffling in the Old Testament, the point of his identity only fully understood by the writers of the New Testament. At times it's as if a mystery writer places clues that he later reveals in his solution one or two thousand years after he's placed them - as if one writer sets the stage in Act One, which he writes in the second millennium BC, and writes the only fitting conclusion in Act Two, which he writes in the first millennium AD
But reading the Bible ain't easy. It must always be done with prayer and patience, and with the best study guides you can find. To that end I heartily recommend the mp3 audio Bible studies of St. Irenaeus Ministries, which can be download here.
To fail to read the written Word of God in our midst is simply to ignore the incarnate Word of God in our midst.