Exodus 34:10-16

10.
Then God said, "Behold, I am going to make a covenant. Before all your people I will perform miracles which have not been produced in all the earth nor among any of the nations ; and all the people among whom you live will see the working of the LORD, for it is a fearful thing that I am going to perform with you.
11.
"Be sure to observe what I am commanding you this day : behold, I am going to drive out the Amorite before you, and the Canaanite, the Hittite, the Perizzite, the Hivite and the Jebusite.
12.
"Watch yourself that you make no covenant with the inhabitants of the land into which you are going, or it will become a snare in your midst.
13.
"But rather, you are to tear down their altars and smash their sacred pillars and cut down their Asherim
14.
-for you shall not worship any other god, for the LORD, whose name is Jealous, is a jealous God -
15.
otherwise you might make a covenant with the inhabitants of the land and they would play the harlot with their gods and sacrifice to their gods, and someone might invite you to eat of his sacrifice,
16.
and you might take some of his daughters for your sons, and his daughters might play the harlot with their gods and cause your sons also to play the harlot with their gods.

Jealousy. In this passage, God reveals part of who He is by calling His name “Jealous.” He is “a jealous God.” He tells the Israelites not to worship other gods because He wants them all to Himself. I find it remarkable that God is making this covenant with Israel even after they have played the harlot by worshiping a golden calf. Furthermore, the omniscient God knows that Israel will play the harlot with the gods of other peoples in the future! And yet He graciously tells them He is jealous for them.
I looked up “jealous” in my concordance and found that the Hebrew word means ardor, zeal, and jealousy. This is a word of passion. God wants His people. He wants them for Himself. He does not want their affections or worship to go to any entity but Himself. In His jealousy He promises to do great things for the Israelites (10) and warns them that worshiping the gods of other people will be harmful to them (11). Yahweh is a God of passion- He ardently desires that His people worship Him alone because He alone is good. He actively desires that His people not worship false gods that will result in their harm.
In Deuteronomy 4, 5, and 6, God’s jealousy is portrayed as a passion so strong that He will visit His love and goodness on thousands of generations for those who love and worship only Him. But, for those who play the harlot, He will punish them greatly.
God wants His people. He pursues them, and loves them jealously.