If Jealousy is Sin, Why Is God Jealous?
The Bible describes God as a “jealous God” (Exodus 20:5) but how can this be reconciled with the Bible’s other statements that God is perfectly good? If jealousy is wrong, how can God be good and yet do something wrong?
Usually, jealousy is a negative trait but in some circumstances it is appropriate. For example, if a wife cares about her husband she will want him to be faithful to her. This is appropriate for her to do since she deserves his exclusive romantic love and faithfulness. In like manner, God is worthy of his people being exclusively devoted to him. So when they stray from him and worship false gods, it is right for God to be jealous.
Josh McDowell, the author of The Bible Handbook of Difficult Verses, explains this further.
As relational beings we can relate to wanting to be loved exclusively. How would you feel if someone said that he or she truly loved you and then cheated on you? It’s not wrong to feel bad about someone cheating on you, is it?…
Of course that kind of jealousy can turn ugly. A person can react to a cheating husband or wife in a wrong manner. The feelings of betrayal (which aren’t wrong in and of themselves) can prompt resentment and hatred and manifest themselves in any number of selfish acts.
But with God being perfectly good and holy, his jealousy is not inappropriately selfish. He knows that when we love him exclusively, with all our heart, soul and strength, it allows us to experience the joy and meaning we are looking for in life... So it is by no means wrong for him to jealously want our exclusive love and devotion. In fact, his jealous love is a model for us to follow.
Josh McDowell and Sean McDowell, The Bible Handbook of Difficult Verses, The McDowell Apologetics Library (Eugene, Ore: Harvest House Publishers, 2013), 83–84.