Yes, there are contradictions, but the one you pointed out is easily explained by pretty much every Christian understanding of the relationship between what Jesus taught and what's in the Old Testament.

So pulling something from Leviticus is irrelevant because that's "the old law" that Jesus came to fulfill. That's like Christianity 101 and one of the few things most denominations agree on.

My personal explanation for the rest of the inconsistencies are losses in translation. The New Testament was preserved by monks transcribing documents by hand, and those monks had a set of existing theological beliefs, so it's highly likely they would prefer a certain wording based on those beliefs. However, I highly doubt things were particularly organized in that translation process, hence the weird inconsistencies (e.g. are Jesus and God the same being, or different?) that tends to result in different branches of Christianity (most today hold the doctine of the Trinity, but many reject it, e.g. Jehovah's Witnesses, Christian Scientists, etc). Many reject my belief that the Bible is a hacked together mess that passed through far too many hands and insist it's infallible (and everything in between).

My point here isn't to push my view of Christianity, but to demonstrate that your comment over-simplifies the issue.