There are different punishments mentioned in this chapter: death, “cutting off from the people” or childlessness. God is simply warning the Israelites that He will not tolerate these types of sins that are commonly committed in Canaan. He is throwing the Canaanites out because of these kinds of transgressions. He is educating the Israelites and doesn’t want them to commit the same sins that got the Canaanites kicked out of the land. God is telling them what is holy and what is unholy.