"You can win the battle, yet lose the war." - Source unknown
Every year, thousands of Jews join the Jews for Jesus movement (a.k.a. Messianic Judaism). This movement aims to repackage Christianity as a form of Judaism - indeed, the fulfillment of what Judaism was supposed to be, before the rabbis mucked things up. This claim is central to their success, because few Jews are actually looking to abandon Judaism.
Those of us who don't believe in Jesus are naturally alarmed by attempts to missionize Jews. We all want to do what we can to counter such efforts. However, it is important to use debate strategies which are not merely correct factually, but convincing to the other side. I list a few below:
DON'T get involved at all, unless you've first learned up their argunents and our counter-argunents. They usually know the Bible better than the average Jew, and they will run circles around you if you don't know your stuff. Some such material may be found here on my website, or at Outreach Judaism. The counter-missionary webring also has a number of good sources.
DON'T go for obvious attacks. Chances are the question has already occurred to them, and either they've thought of an answer, or they're willing to live with the question. Example: "How can you believe in the Trinity when the Bible says there's only one G-d?" Likely response: "I don't understand G-d's essence, but when I get to Heaven, it will all be clear." Or, "How can Christianity be true when it has been resposible for so much bloodshed?" Likely response: "The people who committed these atrocities weren't true Christians. Jesus preached love. These turkeys took his name in vain."
DON'T flame your opponent. S/He is looking for proof that you don't have peace in your heart, because you don't have Jesus in your heart. Avoid words like "absurd" or "come on" like the plague. Be compassinate, remembering that your opponent is him/herself the victim of deception. The Christian's beliefs may be false, but his love for us is real, and the thought of us burning in hell saddens him. Remember also that many of them got into Christianity for emotional reasons, because the first person ever to do them an act of kindness was a Christian. Often they were down and out, from broken families, on drugs, etc., so the apparent proof of their changed lives is not easily shaken.
DON'T assume anything that a Christian wouldn't readily agree to. Quoting the Talmud will have the same impact on him as if he quoted the New Testament to you to support his point. If you wish to argue the translation of a word, you had better be able to show that his Christian translation renders the same word correctly everywhere else. (Sometimes the Christian translation itself is helpful in this regard. For instance, the servant of Isaiah 53 is described as "with the rich in his death"( verse 9). The margin of the King James Bible tells us that the Hebrew has "deaths"; the translator changed the word to make it "clearer". The change is significant because you can speak of a nation collectively in the singular, but you cannot speak of one person in the plural.)
DON'T invalidate his/her feelings. When they are presented with an argument they can't answer, they often fall back on "I feel him in my heart, so I know he's real." The best response is, "Absolutely! I feel G-d in my heart too. He will happily dwell wherever He's wanted." This validates his feelings, while at the same time rendering them irrelevant and steering the conversation back to logical arguments.
DO talk about things you have in common, such as reasons to believe in G-d, Mideast politics, loving other people unconditionally, etc. It is important to develop a rapport and make him/her interested in what you have to say. I once found myself seated next to a Christian fundamentalist on a two-hour plane ride. I spoke with him for almost the entire time about our points of agreement, only occasionally asking questions on his faith. By the end of the plane ride, he agreed that he needed to study more.
DO point out contradictions within the New Testament or between the NT and the Jewish Bible. But do so respectfully. Example: "I'm curious why in Acts 7, Stephen says Abraham came to the land of Canaan after his father died. Back in Genesis, we're told that Terah was 70 when Abraham was born, and lived to be 205. Clearly, then, Terah was still alive when Abraham came to Canaan at age 75."
DO express Jewish concepts in Christian terminology. For instance, when talking about G-d's mercy toward repentant sinners, say "salvation by grace". Hey, it works when they do it to us.
DO undercut the foundation of their faith: the redeeming power of the blood of Jesus. This is also part of the source of their emotional bond ("For G-d so loved the world that He gave His only begotten son etc."). This is a little tricky, because it's easy to get carried away and transgress the first "&don't" by asking why G-d can't just forgive. A better angle is, "Because of our sins, we deserve spiritual death, right?" (He will answer yes.) "But the death Jesus died was a physical death. How can his suffering in this world satisfy the demands of justice upon me, when what I deserve is suffering in the next world?"
DO show why the Jewish laws are eternal and should be kept even by one who believes in Jesus (click here for background on that). Besides the immediate effect of hopefully getting him/her to keep Torah, my experience as a former Jew for Jesus who actually kept things like Shabbos and ate kosher is that this issue can generate conflict with other Christians, thus undercutting their emotional bond to Christianity. This will leave them with nothing except the logic; given enough time, G-d willing, they will ultimately see the error of their ways.
