Why a Jealous God?
We usually view jealousy as something negative, and certainly it can be. We might think of a jealous person as controlling, demanding, and even prone to fly into a rage without the slightest reason.
But in Exodus 20 God says, "You shall have no other gods before Me. You shall not make for yourself a carved image—any likeness of anything that is in Heaven above, or that is in the earth beneath, or that is in the water under the earth; you shall not bow down to them nor serve them. For I, the Lord your God, am a jealous God" (verses 4-5, emphasis added).
God is a loving Father. He loves us and wants an exclusive relationship with us. Is that unreasonable?
If you have children, then I think you are probably a jealous parent. You want the best for your child. You probably think your child is the best at whatever it is that he or she does, whether it’s athletics or music or something else. In the same way, God loves you, and He wants the best for you. So He is jealous in a sense.
I would also think that if you are married, you are probably a jealous husband or wife. How would you feel, wives, if your husband said, "My date is here. I’m going out with her now. Can she borrow that outfit that looks really good on you?" No self-respecting wife would put up with something like that. Nor should she.
God is a jealous God and wants an exclusive relationship with us. He is saying, "You belong to Me, and I have committed myself to you. So that is the way it needs to be." That is the concept being communicated when God described himself as a "jealous" God.