because of the engagement ring of faith ...

An excellent excerpt from ‘Through the Son, Our Lord’: God as Mercy and Love in Martin Luther’s Theology   by Oswald Bayer  - 

“Luther speaks impressively about the ‘happy exchange,’ [Freedom of a Christian] about a transfer, and uses this biblical marriage metaphor, and the way it is used, to characterize the mystique of the bride.  This is expressed paradigmatically in On the Freedom of a Christian, section 12: faith ‘binds the soul with Christ, just as the bride with the bridegroom.  By means of this secret (as the apostle teaches [Eph. 5:32]) Christ and the soul become one flesh.’ [WA 7:54.3f.; cf. LW 31:351]

 ‘Since Christ is namely God and human in on and same person, who not only has not sinned, not died, and is not damned, but instead neither can sin, nor die, nor be damned, and because his righteousness, his life, his salvation is unconquerable, eternal, almighty—because, I say, such a person become one with the sins of the bride, her death and her hell because of the engagement ring of faith, and in fact makes them his own, and acts in no other way than as if they are his own and as if he himself had sinned – going through great exertions, dying, and descending into hell – so that he could overcome everything and, because sin, death, and hell could not swallow him up, everything therefore is swallowed up in him [“absorbed,” 1 Cor 15:54] by means of a battle between two that awakens astonishment.  For his righteousness is spread out over the sins of all, his life is stronger than every death, his salvation is more invincible than any hell.  In this way the believing soul is freed from all sins by the dowry; its faith in Christ, its bridegroom, is safe in the face of death, and is protected from hell, because the eternal righteousness as well as the eternal life and salvation of its bridegroom Christ are all given to it as gift.  Thus he creates himself a magnificent bride without spot or wrinkle, since he purifies her in the bath with water through the Word of life [Eph. 5:27, 26], that is, through what is worked through faith, which comes through the Word, through life, through righteousness, and through salvation.  Thus he betroths himself to her in faith, in mercy compassion, in righteousness and judgment, as it is stated in Hosea 2[:19-20].’  [WA 7:55.7-23 (Translation of the Latin version)] ” 

pg. 225-226

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