Anything you say, do, or think that is contrary to what God desires is considered sin. Sin is the failure to do what is right, and sin offends people because it is wrong, unloving toward others, and ultimately rebellion against God. Furthermore, according to the Bible, sin is a condition in which the heart has a proclivity toward evil. The most serious aspect of sin is that it is the sole cause of our separation from God. Sin cannot exist in God's presence because he is holy. As a result, it is what separates us from him.