Well, I guess you could say Judaism was the birthplace of legalism. They took the 613 laws of the Torah and expanded them to thousands in order to not break the 613. Now, of course, their intentions were good, but we all know what road is paved with good intentions. The one error rule grows out of a deep but misguided respect for God's word. Another thing the Jews did was try to avoid saying God's name. The thinking was if you never say it you can't take it in vain and be guilty of breaking that commandment. An idea that focuses way too much on one's actions and not on ones attitudes and motives, which is an issue Christ was constantly confronting.
Originally, Hebrew didn't have any vowels, just consonants. Eventually, someone came up with a system to add points or dots to Hebrew words in order to indicate vowels. Well, to avoid even writing God's name, the scribes decided to use the consonants for Yahweh, but they used the points or dots (vowels) for Adonai which is the word for "Lord". When literally translated, you get the word Jehovah, which isn't a real Hebrew word at all but a combination of the consonants for Yahweh and the vowels for Adonai. I would think this would present a problem for Jehovah's Witnesses, but that's another story.
Hamp, it's not that Orthodox Jews don't believe the NT, they just don't think it's scripture … God's word. They would read it for historical value, but do not believe that Jesus is the Messiah. There are, however, Jews who do believe Jesus is their Messiah, they usually call themselves Messianic Jews or completed Jews. Jews for Jesus is one such group. You could get more info from Sarah's family on this topic.
If you have a Jewish friend and want to introduce them to Christ, give them a copy of Matthew. It was written specifically for them.
Dad