Mark 10:6-9

This brief Gospel from Mark gives the Catholic teaching on marriage its leanest possible expression. Jesus, asked about divorce, answers by going straight back to Genesis: "from the beginning of creation, God made them male and female... the two shall become one flesh. So they are no longer two but one flesh. What God has joined together, no human being must separate."

In just a few sentences, Mark recovers the entire biblical theology of marriage. There is no extended argument, no nuance about exceptions; there is only the original gift, named with full force. Marriage is from the beginning. It is one flesh. It is what God himself joins. It is not human beings' to separate. For a Catholic wedding, choosing this Gospel is choosing the most concentrated possible statement of what the sacrament involves.

The "one flesh" image is worth lingering on. It is not poetry. The Catholic tradition takes it seriously as a description of what happens in valid sacramental marriage: a real, mysterious unity is established that goes beyond the sum of two individual lives. The couple becomes, in some genuine sense, a single thing. That is why the Church has guarded the indissolubility of marriage so carefully, because what God has actually done at the altar is not the kind of thing that can be undone.

For couples who want the Gospel itself to do most of the theological work of the wedding, proclaiming, in the briefest possible compass, the whole Catholic vision of marriage, Mark 10 is the right choice.