There are several verses in the Bible that refer to God as being a “jealous God.” These verses are often misunderstood. This is because we are accustomed to jealousy being defined as “being envious” or as being “bitterly resentful, or suspicious of a rival or of a rival’s influence.” This is not the intended meaning of the word jealous when used in reference to God. A better translation is “zealous.”
Another definition of jealous is “protective or vigilant in guarding one’s rights or possession.” This is the proper sense in which we should understand this word as applied to God. God demands faithfulness and exclusive worship. He will not tolerate that the reverence due to Him, should be given to another being or inanimate object (Exodus 20:5). He has a burning zeal for His own glory, and He guards it with care (Deuteronomy 4:24; Hebrews 12:29).