What does the description of God as “jealous” mean?

Exodus 20:4-5“You must not make for yourself an idol of any kind or an image of anything in the heavens or on the earth or in the sea. You must not bow down to them or worship them, for I, the Lord your God, am a jealous God who will not tolerate your affection for any other gods. I lay the sins of the parents upon their children; the entire family is affected—even children in the third and fourth generations of those who reject me.”

Jealousy is usually described in negative terms, but it can also mean “a demand for complete devotion.” In this respect, a husband and wife are supposed to be jealous for each other, expecting that they will share their most intimate love with no one else. Likewise, God is jealous for the undivided devotion of his people. When people give their honor, praise, and love elsewhere, God is jealous that the honor due him has been squandered. Because God deserves all our honor, praise, and love, our worship of him alone is an honest recognition of what he deserves.

Exodus 34:14“You must worship no other gods, for the Lord, whose very name is Jealous, is a God who is jealous about his relationship with you.”

Deuteronomy 5:9“You must not bow down to them or worship them, for I, the Lord your God, am a jealous God who will not tolerate your affection for any other gods. I lay the sins of the parents upon their children; the entire family is affected—even children in the third and fourth generations of those who reject me.”

Deuteronomy 32:21“They have roused my jealousy by worshiping things that are not God; they have provoked my anger with their useless idols. Now I will rouse their jealousy through people who are not even a people; I will provoke their anger through the foolish Gentiles.”

Zechariah 1:14Then the angel said to me, “Shout this message for all to hear: ‘This is what the Lord of Heaven’s Armies says: My love for Jerusalem and Mount Zion is passionate and strong.’”

We cannot love God and someone or something else equally. God’s jealousy is not petty but springs from deep love and a desire for our best interests. Jealousy understood like this is essential to trust in any relationship. Because God deserves all our honor, praise, and love, this honest emotion recognizes that divided loyalties (between God and our idols) only harms our relationship with him and therefore deeply harms us.