Idolatry 2.0

1 John 5:21 tells us to stay away from idols, but why does John tell us this after spending 5 chapters assuring us of our salvation and relationship with the Lord. He did this because he knows that as humans, it's easy for us to make things about us instead of remaining submitting to the Lord and we slowly start to make God in our image instead of remembering that our freedom is found in Him.