Scot McKnight has some helpful thoughts on the nature of God’s jealousy inspired by reflections on the second commandment:
God is “jealous” for his love and that is why idol-making is wrong. A little lesson: “I’m sooo jealous” is a commonplace expression today, but it’s an erroneous one most of the time. Most of the time it means “I’m so envious.” We envy what others have; we are jealous of what we have. God is not envious of us and what we are doing. God’s honor is wounded, his glory is clouded, and his love is broken when any of us decides to focus our love and our worship and our allegiance to anyone but God. God is Jealous for his love and for his glory and for his honor.
That the point of idol-making has to do with God’s Jealous love complements what Jesus said: the laws are about either loving God or loving others. The 2d Commandment is about loving God and we don’t love God if our loyalty is split.
I’m not so sure about the language of God’s “honor” being “wounded” but the distinction between envy and jealousy is quite important and helpful.