Q: Since we have the New Testament, and it’s about Jesus, why should we continue reading the Old Testament?
A: To better understand Jesus Christ. When we read about the apostles and all the disciples in the New Testament (NT) we should remember that the only Bible they had was what we call the Old Testament (OT). The apostles and disciples never expressed any dissatisfaction with the OT, and certainly didn’t wait for the NT to be written in order to proclaim Christ. By the Holy Spirit, they saw Christ from one end of the Old Testament to the other. And if our English Bibles capitalize OT quotes in the NT, we can see this for ourselves. Let us therefore keep looking for Christ in the Old Testament, for that is the ultimate purpose for which it was written.
This answer first appeared as a comment on a blog post titled “Three reasons to keep reading the Old Testament” by Aaron Armstrong, who writes at Blogging Theologically: Jesus, Books, Culture, & Theology.