In the Bible God tells His people that they are different, and should behave themselves so. We as Christians are to be very different from the world around us. This might cause people to wonder what planet we’re from, but God calls us to be different because He calls us to be like Him. In Leviticus 11:44-45 and 19:2, God says to be holy because He is holy. Now while many of the laws and promises for the Israelites in the Old Testament do not apply to us Christians today, there are principles to be learned from them. We know this especially if something is quoted later in the New Testament. For example, 1 Peter 1:15-16 references Leviticus.
In Leviticus God gives some very specific laws about how His people, the Children of Israel, were to behave. God told the Israelites that they had these laws so that it was readily apparent that they were not like the people around them. They were to have and live by these laws to show people that God was with them. They were to have and live by these laws to make it very clear that God is holy and requires that His people be so as well. See these principles in Leviticus 10:8-11, 18:1-5, and 20:23-26. Things were supposed to be very different for the Children of Israel. If you read throughout Leviticus, you’ll also notice that God says “I am the Lord” after many commands, implying that you keep them simply because He is God and He said so.
We must remember that God is God. We must remember that we don’t make ourselves holy, God makes us holy. We must remember to be holy because God is our God. (Leviticus 20:7-8)