The marriage vows mark marriage out as an ascetic discipline.
As the Wesley hymn explains:
“The Church’s one foundation/ Is Jesus Christ her Lord/ . . . From heaven he came and sought her/ To be his holy bride;/ With his own blood he bought her,/And for her life he died.”
The controlling New Testament interpretation of marriage relies upon Genesis, yet— notice—Paul does not associate marriage with procreation or with complementarity, but with typology: with God’s plan to love and save his people, one God, one people.
Same- and opposite-sex couples seek to participate not in something natural but in something unnatural— something known to us only by revelation— this typology of marriage.
It belongs to the church’s mission to introduce them into that witness and discipline.
The question of same-sex marriage therefore comes to the church not as an issue of extended rights and privileges (this is why the language of “full inclusion” is insufficiently Christian language, I believe) but as a pastoral occasion to proclaim the significance of the gospel for all who marry, because marriage embodies and carries forward the marriage of God and God’s people.
Because the marriage rite itself presumes that marriage is about sanctification, to deny committed couples marriage deprives them not of a privilege but of a medicine.
“It deprives them not of a social means of satisfaction but of a saving manner of healing. Those couples who approach the church for marriage– and those whose priests prompt them to marry—are drawn there by the marriage of Christ and the church, which alone makes it possible for human relationships to become occasions of grace” (Eugene Rogers).
Couples who delay marriage are like those who previously waited for deathbed baptism.
They unaccountably put off the grace by which their lives might be healed. Likewise, the Church which denies them marriage may be like the priest who fails to show up and offer them a saving rite.
There is no question of whether the marriage of Christ and the church is available to sinners.
Only, how it is so.
The church must know how to respond both to couples who seek marriage and those who delay it. Among those who seek marriage are same-sex couples who offer their relationship in witness to and imitation of Christ’s love. Among those who delay are same-sex couples waiting for the church to discover and proclaim the significance of its marriage to Christ for their relationships. In both cases, the church faces a test of its understanding of atonement, posed in an immediate pastoral query. How will the church receive the couple that would approach the altar, and how will it suffer the couple that delays?
How the church marries couples shapes its witness to Christ’s atonement. Whom the church marries testifies to its understanding of its own sanctification. The church’s practice of marrying is an evangelical practice, proclaiming that the love of God for God’s people is real, that the atonement is real, that reconciliation is real, that salvation is real. The Spirit calls all Christians to witness to that reality, and the church offers practices for doing so.
Because the love of God for God’s people is real, and the declaration “this is my body given for you” is true, the church needs as many witnesses as the Holy Spirit and its mission may draft. Same- and opposite-sex couples who want to marry in the church bear witness to the love of God for God’s people and to the power of that love to atone, reconcile, and heal. Not that they can do those things by their human power alone, but the Spirit can attest their witness to the atonement and healing of Christ.