My original question (to which I'm assuming you were replying to) was: If it is not against Christianity to practice and observe Jewish rites and traditions, then why don't Christians do so?
Hmm...damn good question, and one that I personally don't have a good answer for you, to be honest.
I can make some wild guesses...
- Many Christians don't understand Judaism. There may also be many Christians that think they understand Judaism but instead hold a perception that Jewish folks feel is inaccurate.
- Many Christians who are learned spend more time in study devoted to their own faith than in study devoted to other faiths.
- Fo Christians, belief in Jesus is a necessary condition. As such, the New Testament, particularly the Gospels, are typically emphasized more than the Old Testament.
- Christianity doesn't teach Jewish traditions.
- The two faiths progressed as seperate faiths, each developing their own branches, cultures, and traditions over the past 2000 or so years.
- There isn't much "encouragement" for the cultures to intermingle.
- Jews are a distinct minority in the US (and most other places where there are a high percentage of Christians). Outside of Israel, the Jew has had to adapt to the Christian more than the Christian has had to adapt to the Jew.