“What, then, is marriage for?,” Tim Keller asks in The Meaning of Marriage. He answers, “It is for helping each other to become our future glory-selves, the new creations that God will eventually make us. The common horizon husband and wife look toward is the Throne, and the holy, spotless, and blameless nature we will have. I can think of no more powerful common horizon than that, and that is why putting a Christian friendship at the heart of a marriage relationship can lift it to a level that no other vision for marriage approaches.”
Then he gives this helpful illustration.
“Have you ever traveled to a mountainous part of the world when it was cloudy and rainy? You look out your windows and you can see almost nothing but the ground. Then the rain stops and the clouds part and you catch your breath because there, towering right over you, is the magnificent peak. But a couple of hours later the clouds roll in and it has vanished, and you don’t see it again for a good while. That is what it is like to get to know a Christian. You have an old self and a new self (Ephesians 4:24). The old self is crippled with anxieties, the need to prove yourself, bad habits you can’t break, and many besetting sings and entrenched character flaws. The new self is still you, but you liberated from all your sins and flaws. This new self is always a work in progress, and sometimes the clouds of the old self make it almost completely invisible. But sometimes the clouds really part, and you see the wisdom, courage, and love of which you are capable. It is a glimpse of where you are going.”