One of the most comforting things about Christianity is knowing we have a God who isn't just trying to wing it. He's not making things up as He goes along, neither is He failing and resorting to plan B. Rather, what we see in the scriptures is a carefully constructed plan being put into action piece by piece.
The New Testament is not so new that the Old Testament seems to have failed. Far from it, the prophets eagerly awaited the day when God would make a new covenant. The Old covenant made with Moses had a purpose; a purpose which has been served, completed at the cross.
The Bible is a great masterpiece. Every word is like the stroke of a brush. Every verse a new thread. From beginning to end, God shows His genius. Through the miracle of prophecy, God told our ancestors what to look out for. Through historical study, God shows us that He always intended things to turn out this way. What a God we serve!