You search the Scriptures because you think that in them you have eternal life; and it is they that bear witness about me, 40 yet you refuse to come to me that you may have life. I do not receive glory from people. But I know that you do not have the love of God within you. I have come in my Father’s name, and you do not receive me. If another comes in his own name, you will receive him. How can you believe, when you receive glory from one another and do not seek the glory that comes from the only God? Do not think that I will accuse you to the Father. There is one who accuses you: Moses, on whom you have set your hope. For if you believed Moses, you would believe me; for he wrote of me. But if you do not believe his writings, how will you believe my words?” John 5:39-47
In sum then, you can test yourself and others as to whether you know God, or honor God, or love God. And the test is Jesus. Any claim by a Jewish person or a Muslim or a Hindu or a Buddhist or a spiritualist or an animist or a Christian—any claim to know God or honor God or love God while not receiving Christ as the Son of God and the crucified risen Savior is a false claim. The measure of all true knowing God, honoring God, and loving God is knowing, honoring, and loving Jesus for who he really is.
Therefore, Christian—whether Jew or Gentile—embrace your Scriptures. All of them. Both Old Testament and New Testament. Because in them you come to know God for who he really is, and that means coming to know Jesus. For all of them witness to him and speak of him.