Piper, who has been married the longest of the three, began the discussion by recalling what the famed German pastor Dietrich Bonhoeffer told a young couple about to enter into holy matrimony: "It is not your love that sustains the marriage, but from now on, the marriage that sustains your love."
The covenant, from this day forth, sustains the love, not the love the covenant, emphasized the author of Desiring God.
"I, at 42 years of marriage, feel very strongly that [Bonhoeffer] is emphasizing that romance and falling in love is a beautiful thing, and re-falling in love, again and again, is important... [But] re-falling in love after seasons of pain can be sustained only if you elevate covenant above those affections and romance," Piper stated.
Piper's main message to those looking to marry or who were already married was that affections should never be the foundation of marriage because while affections were here one day and gone the next, it was the covenant – the vow made to each other – that withstood the test of time and patience.
"You have covenanted, and God has thus united – that covenant exists. Your affections, they exist, and then they don't exist. You get angry, and then you don't get angry. You feel so mad and you wonder where did all that affection go? And that can be reborn because there's this massive platform."
Rephrasing Piper's statement in more popular terms, Carson quoted what one man who had been married for over 60 years said during an interview on British television.
"The interviewer [asked the man], 'During all the time, haven't you ever considered divorce?' And he said, 'Divorce, divorce, never. Murder, often. Divorce never.'"
"Obviously," the Canadian-born professor expressed, "you can make that sound ridiculous. But he's got a point."
Keller, who agreed with the man on the television, reinforced the point made by the other two theologians by referencing an article by Lewis Smedes on the Christianity Today website entitled, "The Power of Promising."
Smedes wrote, "My wife has lived with at least five different men since we were wed – and each of the five has been me."
"And he says the one thing, the thread that kept all five of them together, is [his] promise," the pastor of the Redeemer Church explained. "He's trying to get across the fact that you change, your spouse changes...and so the basis of your marriage can't be the feeling...can't even be 'we're just kindred spirits' because your spirits will go in and out of being kindred."
"The thing that keeps it is the promise," he added. "I made a promise. I made an appointment with you in the future to be your husband, every year... it's a covenant."
Worried that the "covenant" might sound "too duty-oriented" to some, Piper noted, "That's the ground in which the flower grows."
"Because if you're in a season right now where the flower is wilted and you think the solution is to pull the plant up, that's not the solution. The ground of covenant, the ground of promise, the ground of no divorce, maybe murder, that's the ground where it can re-flourish. And it does," he concluded, personally testifying to 42 years of falling in love with his wife NoÃ"l Henry, over and over again.
"We are testifying by our perseverance in covenant keeping something about Christ and the church in covenant with each other," Piper affirmed. "We lie about Christ and we lie about what the church is obliged to do if we leave her."
For Christians, the key to marriage did not just rest upon a promise made for better or worse, for richer or poorer, and in sickness and in health, but on an everlasting covenant sealed in Christ, where "neither death nor life, neither angels nor demons, neither the present nor the future, nor any other powers, neither height, nor depth, nor anything else in all creation" could separate, the theologians sought to convey.
"When we make and keep promises," Smedes penned, "we are most of all like the God whose name is 'I am he who will be there with you.' Among all the dimensions of the mature person in Christ, none comes closer to the character of our Lord than the daring to make a promise and the courage to keep the promises we make."