I’m reading a lot of Jewish authors as part of my research for a book I’m writing on how to witness to Jewish people. I’m reminded of things I heard from childhood while learning some other things for the very first time. It’s helpful to sense why people believe what they believe and not just list the specific tenets of their faith.
Many Gentile Christians are often baffled by some of the things they hear from Jewish people. Some strongly held convictions seem to be (and often are!) blatant contradictions to what we find in the scriptures.
One possible root cause of this problem is that many observant Jewish people believe in two revelations from God – a written one (what we have in the Tenach – the Hebrew term for what Christians call The Old Testament) and an oral one, both given to Moses on Mt. Sinai. Moses wrote down what God wanted written and he spoke what God only wanted spoken. That oral revelation eventually did get written down as the Talmud and Midrash (and possibly some other writings).
On one hand, we Christians need to be slow to condemn what seems like divine duplicity because, if God wanted to reveal a written revelation as well as an oral one, who are we to say he can’t. On the other hand, there are far too many places where the two so-called revelations, as we now have them, contradict each other terribly. I believe this accounts for much of the wide variance between the Judaism we read about in the Tenach and what we see in the lives of many modern Jewish people.
Most rabbis would say that both revelations are equally inspired and equally authoritative. And I think most would say there are no contradictions between the two. But when it comes down to it, there are irreconcilable differences that lead Jewish people away from the truths of God’s written word as found in the Bible.
For example, in Rabbi Benjamin Blech’s popular book The Complete Idiot’s Guide to Jewish History and Culture, we find this discussion about the Jewish people being called “God’s chosen people.”
“It might be comforting to believe that Jews were selected from among all other peoples as some kind of divine acknowledgment of their excellence. But Jewish sages tell the story somewhat differently. In the Midrash [ancient commentaries], God goes to all the nations of the world and asks them whether they would be willing to accept His commandments. Every one of them asks first for the details. What does He demand from them? When given specifics — things such as not stealing, killing, and adultery — they beg off; such laws would interfere with their lifestyles. Only the Jews were willing to accept. That, say the rabbis, makes them not the chosen people, but rather the choosing people.” 
The quote starts in the direction that seems humble. “Maybe God didn’t see something excellent in us.” So far, so good. But then, in not so subtle terms, the writer (and the ones he references from the Midrash) asserts that Jewish people are better than other peoples. “We didn’t reject God’s offer the way they did. We didn’t allow our own lifestyles to take priority over God’s commandments. We chose God.”
We must remember, by the way, that the Tenach does indeed say that God chose Israel. A quick word search of “chosen” will offer ample evidence, even if you limit yourself to the book of Isaiah. For example, in Isaiah 41:8-9, we read, “But you, O Israel, my servant, Jacob, whom I have chosen, you descendants of Abraham my friend, I took you from the ends of the earth from its farthest corners I called you. I said, ‘You are my servant’; I have chosen you and have not rejected you.”
And to press the point further, Deuteronomy 7:7-8 says, “The Lord did not set his affection on you and choose you because you were more numerous than other peoples, for you were the fewest of all peoples. But it was because the Lord loved you and kept the oath he swore to your forefathers that he brought you out with a mighty hand and redeemed you from the land of slavery, from the power of Pharaoh king of Egypt.”
We could say a lot more about God’s choosing being based on his love and not on Israel’s loveliness. I hope you can say the same and far more about your own new identity as a redeemed child of God, saved by grace, and loved in spite of your rebelliousness.
But I also hope we all might pause just a bit before condemning the notion of “two divine revelations.” Don’t we all have a tendency to sometimes attribute too much authority to some non-Biblical works? We would deny we believe those works have the same authority as the Bible. But, in practice, might we look to favorite authors, most-used commentaries, historical documents (e.g. Calvin’s Institutes, The Westminster Confession), or even recently listened to sermons for more prominence than they deserve? Even worse, in practice, couldn’t we sometimes allow the lenses of popular psychology, successful business practices, or even pop-culture to dictate what we say and how we say it?
We who believe in sola scriptura would do well to reflect on the longest chapter in the scriptures, Psalm 119, and marvel that God has indeed revealed his word which is, “eternal; it stands firm in the heavens” (Ps. 119: 89). To this God, we should offer praise and say, along with the Psalmist, “Oh, how I love your law! I meditate on it all day long….How sweet are your promises to my taste, sweeter than honey to my mouth!” (Ps. 119: 97, 103).
 Blech, Benjamin. The Complete Idiot’s Guide to Jewish History and Culture. Alpha Books, New York, NY. 8.