1 Samuel 15:23

For rebellion is as the sin of witchcraft, or divination, the service of demons in any form, and stubbornness, in refusing to obey God's commands, is as iniquity and idolatry, in which the living God is denied and rejected. Because thou hast rejected the word of the Lord, he hath also rejected thee from being king, Saul was abandoned to his pride, selfishness, and wickedness. He who opposes the Word of the Lord in any way, whether by speaking or by doing, thereby denies the true God and is in danger of being rejected.