If this is true [the validity of Torah to our present lives]…how did Christians miss it for long (and so many still do)?
It occurs to me that when we ask that question we are assuming the same thing has been believed since shortly after Yeshua walked the earth. That is simply not the case. Why don’t we ask the question, “How did 1500 years of Godly men miss the truths that God revealed to Luther, Zwingli and Calvin?” Of course, there are a lot of answers to that question. Similarly, there are a lot of answers to why did the Reformers and most theologians since miss the applicability of the Old Testament to our lives?
I think it is vital to focus on the evolution of theology. We tend to think that what we believe is what most Christians have believed for centuries, but that is simply not the case. Dispensationalism, the theology behind what many of us take for granted, is a very recent development. It didn’t even appear on the scene until the late 1890’s and didn’t become a force to be reckoned with in Christianity until the 1940-50’s. I have a diagram that I use to try and visually illustrate this concept in tandem with the concept of Progressive Revelation. (http://www.cyberhedge.net/docs/History_of_Theology_diagram.pdf )
Progressive Revelation is very important to answering this question. I find it helpful to focus on the covenants; while Paul makes it very clear that a later covenant cannot annul a previous covenant (Gal. 3:17), what God does in each of His covenants, even in each subsequent stating of the same covenant, is get more specific as to all the details of His eternal plan. For example, Abraham knew that God was going to bless all nations through his Seed. Moses finds out that God intended to inaugurate a very special, covenant relationship with a group of people. David finds out that not only is the promise of God going to be fulfilled through Israel, God’s covenant people, but that it will be through David’s family line. Yeshua reveals the specifics of how God is going to redeem us from our spiritual Egypt. This progressive revelation of information seems to be a consistent practice with God.
Note that throughout history God has incrementally added more and more books to His Word to us. Abraham may have had a form of the book of Job. Moses writes the Pentateuch. Samuel contributes more. By the time of Ezra there is a skeleton of our Old Testament. By 367 CE there is a general acknowledgement of the books that we now call the New Testament. But for 300 years after Christ, believers did without the New Testament–at least as a codified, reliable collection of Scripture.
Here’s a possible reason that seems to make sense, but that I can’t prove. Perhaps God allowed the “partial blinding” or “partial hardening” of hearts to certain truths for a time in order to facilitate a massive infusion of Gentiles to His covenant people. There is certainly established precedent of God doing this. Paul tells us that God veiled the eyes of the Israelites at Sinai so that they would not understand the fullness of His covenant with them (2 Corinthians 3:12-16). In Romans Paul tells us that God has partially hardened the Jews until the fullness of the Gentiles have come in (Romans 11:25).
Perhaps He did the reverse to allow large numbers of Gentiles to come in-Gentiles who would have been hesitant if Christianity had been widely perceived as a “Jewish” religion over the centuries. After all, prior to Pentecost, though there had always been Gentiles (strangers, aliens, sojourners) among the congregation of Israel, that believed in God (God-fearers) they were a small minority. Conversely, by the time Paul wrote the letter to the Roman congregation, it appears that 80% of the synagogue in Rome may have been Gentile (based on the list of names in Chapter 16 of Romans – thank you, Mark Nanos, for that idea).