These few verses from the Sermon on the Mount give Christian marriage one of its most important self-understandings: the marriage is not for itself alone. It is salt for the earth and light for the world. The love between you is meant to be visible, useful, and pointing beyond itself to the Father in heaven.
Jesus' two images are gentle but pointed. Salt that has lost its savor is good for nothing, and a marriage that turns inward, that withdraws from the world, eventually loses what makes it distinctively Christian. Light placed under a basket is wasted, and a marriage that hides its faith, that conforms quietly to the surrounding culture, fails to give the witness the world needs to see. The Catholic tradition has long understood marriage as a public sacrament for exactly this reason. Your love is meant to bear public fruit.
The closing line, "let your light shine before others, that they may see your good deeds and glorify your heavenly Father", gives the marriage its missionary horizon. You are being sent, as a couple, into the world. The hospitality of your home, the witness of your fidelity, the patience you show your difficult relatives, the quiet generosity you extend to neighbors and coworkers: all of this is meant to make God's kindness visible. Marriage is not the destination; it is the launching point.
For couples who understand their marriage as a vocation that includes witness, this Gospel is a perfect fit.
