Questions for Christians only, about the Bible?

If you go back into the Old Testament it is saying it is pretty much against it but it says that if you do own slaves treat them fairly and release them after four years. There is always stuff in the the Bible that is in the law such as smoking it is said that you shouldn't let intoxicating(stuff that could harm you) things into your body. God is the Judge of the Universe and will do what is right what He chooses to do is up to Him but just know it is right. Hope this helps.