The warning that is added ought to be of no little avail in shaking off our sloth. He threatens that: “I, Jehovah your God, am a God (or, ‘mighty’; for this name of God is derived from ‘might’), [who is] jealous, visiting the iniquity of the fathers upon the children, unto the third and the fourth generation of those who hate my name, but showing mercy to thousands of those who love me and keep my commandments.” [Exodus 20:5-6 p.]. . . . He declares that he will vindicate his majesty and glory against any who may transfer it to creatures or graven images. . . . And that is by no brief and simple revenge, but one that will extend to the children, the grandchildren, and the great-grandchildren, who obviously will become imitators of their fathers’ impiety.
God very commonly takes on the character of a husband to us. Indeed, the union by which he binds us to himself when he receives us into the bosom of the church is like sacred wedlock, which must rest upon mutual faithfulness [Ephesians 5:29–32]. As he performs all the duties of a true and faithful husband, of us in return he demands love and conjugal chastity. That is, we are not to yield our souls to Satan, to lust, and to the filthy desires of the flesh, to be defiled by them. Hence, when he rebukes the apostasy of the Jews, he complains that they have cast away shame and become defiled with adulteries [Jeremiah chapter 3; Hosea 2:4 ff.; cf. Isaiah 62:4–5]. The more holy and chaste a husband is, the more wrathful he becomes if he sees his wife inclining her heart to a rival. In like manner, the Lord, who has wedded us to himself in truth [cf. Hosea 2:19-20], manifests the most burning jealousy whenever we, neglecting the purity of his holy marriage, become polluted with wicked lusts. But he especially feels this when we transfer to another or stain with some superstition the worship of his divine majesty, which deserved to be utterly uncorrupted. In this way we not only violate the pledge given in marriage, but also defile the very marriage bed by bringing adulterers to it. (Institutes, 2.8.18)