Why should I still read the Old Testament?

Luther:

Because of three reasons. Firstly the laws that are in it are not actually in force for use, but they are still very useful. I do not hold them because Moses commanded them, but because Moses’ laws correspond to nature. Secondly because there are promises in them that can reinforce my weak faith. And thirdly because of the gorgeous examples of faith, love and hope shown by the beloved holy patriarchs. By means of their example we learn to trust God and to love Him.