God’s name is the epitome of who and what He is, and He says His name is Jealous. Jealousy is not merely a passing mood with God. It is the essence of His person. He cannot be other than jealous. Since He is the highest and greatest being there is, infinitely holy and glorious, He must be passionately committed to preserving His honor and supremacy. He must zealously desire exclusive devotion and worship. To do less would make Him less than God.
Richard Strauss