John Calvin aptly described the faithful jealousy of our God and how it speaks of His love for His people:
The more holy and chaste a husband is, the more wrathful he becomes if he sees his wife inclining her heart to a rival.Any husband who met his bride's adultery with indifference would be unloving and rightly described as unfaithful himself! And our Lord is the holiest of husbands. His jealousy is His holiness, faithfulness, and love expressed against the sin of His bride.
In like manner, the Lord, who has wedded us to himself in truth, manifests the most burning jealousy whenever we, neglecting the purity and his holy marriage, become polluted with wicked lusts.
- Institutes of the Christian Religion, I.VIII.18.
It is in glory that He is provoked to jealousy in faithfulness and in love for His bride - redeemed by Him, called by His name, and covenanted to Him in love. We are His Temple, "bought with a price" (1 Cor 6:19-20). We are His Bride, for whom He died in His love "that He might sanctify here... that she would be holy and blameless" (Eph 5:25-27).
So wedded to the Lord by the blood of Jesus His Son and by the bond of the New Covenant, we are instructed to flee immorality. Our husband loves us faithfully. Let us seek His glory in purity until we recline at His side forever at the marriage supper of the Lamb.