There’s a term that I’ve heard for a while that I’m growing unfond of. That term is “New Testament Christian”. I completely understand what is meant by it, I just don’t use it myself.
If you’re unfamiliar with the term, it simply means that you follow the New Testament pattern and order of things. I agree with this assessment because Jesus fulfilled the law of Moses (Matthew 5:17-18) so we are no longer bound to it. We now live under the law of Christ. To me, it just seems redundant to say “New Testament Christian” as it should be implied. Just saying ‘Christian’ should suffice.
Some have even taken this a step further and use “Bibles” comprised with only the NT in it. This may give the wrong impression to outsiders that you don’t want. It may give the impression that the Old Testament isn’t important to look at or study and that’s simply not the case. We should never under estimate impact of the OT. Even Paul says we are to learn from it (Romans 15:4).
You really can’t even understand the New Testament without the foundation laid by the Old. Much of it wouldn’t make sense, like the terms used and rituals done. You wouldn’t even know why Jesus came to die in the first place.
Let’s not forget too, that during the NT times, the NT wasn’t written yet. So, when the apostles and other disciples after them, were preaching to people about Jesus, they would have used the writings of the prophets and wisdom literature. They had to show the masses that these writings pointed to Jesus’ coming, death, and resurrection. It’s what the Bereans used to check Paul and Silas (Acts 17:11) and Jesus, Himself, had to tell people on occasion that certain passages spoke of Him (cf. Luke 24:44).
So, while it is true that we are no longer under the Law of Moses and have no need to abide by it, we still have an obligation to learn from the stories and read the many prophesies that pointed to Jesus of Nazareth as the then coming King of Israel that would suffer and die to be able to forgive them of not only their sins, but the sins of the whole world (John 1:29; 1 John 2:2).