My discovery of the J-Curve began in the late 1980s after I’d written a course on how the gospel applies to our lives. I noticed the apostle Paul didn’t just preach the gospel, he relived it. This passage from Colossians 1:24 and others like it caught my attention:
Now I rejoice in my sufferings for your sake, and in my flesh I am filling up what is lacking in Christ’s afflictions for the sake of his body, that is, the church.
It seemed strange, almost uncomfortable, that Paul says he rejoices in his sufferings. Most of us endure or cope with suffering, but we don’t rejoice in it. Then he says he is suffering for their sake. How can he suffer for the believers in Colossae? He isn’t even close to them; he is in Rome, a month’s travel from Colossae.
Strangest of all, he says he is filling up what is lacking in Christ’s afflictions. How can anything be lacking in Christ’s afflictions? Jesus’s death was “once for all.” I’d never thought about this before. It seemed new and strange. I’d seen this verse applied to missionaries who suffered for the gospel, but not to me, not to everyday life.
THE FELLOWSHIP OF CHRIST’S SUFFERING
Paul’s letter to Philemon, the companion letter to Colossians, especially riveted me. It’s where I first discovered the J-Curve. Philemon, a wealthy leader in the church in Colossae, had a slave named Onesimus who ran away to Paul in Rome and was dramatically changed by his encounter with the apostle.
Paul sent Onesimus (his name means “useful”) back to Philemon with this letter, which was read to the entire congregation. In the letter, Paul asks Philemon not only to accept Onesimus, but to welcome him as a brother. Paul hints that Philemon should give Onesimus his freedom. The gospel permeates Paul’s assumptions as he makes his case to Philemon. Look at Paul’s seemingly innocuous comment to Philemon about Onesimus, the runaway slave:
I would have been glad to keep him with me, in order that he might serve me on your behalf during my imprisonment for the gospel. (Philem. 13)
Paul suggests that Philemon “gift” Onesimus to Paul “that he might serve me on your behalf.” Just as Jesus died for us, Paul assumes Philemon will want Onesimus to serve on Philemon’s behalf. This is an expensive assumption—a male slave could be valued at as much as $150,000 in today’s figures. For Paul, the lived-out gospel trumps Philemon’s property rights (according to Roman law, he owns Onesimus) and Roman justice (Onesimus ran away).
Paul invites Philemon into a fellowship of Christ’s sufferings (Phil. 3:10) in an offhand way, sure that Philemon has the same perspective. Paul presumes that Philemon considers substitutionary love normal. “The DNA of Jesus has so shaped Paul that he can’t imagine a Christian life that isn’t radically shaped in this same way.”
THE J-CURVE IS NORMAL
Later in the letter, Paul offers to substitute himself for Onesimus:
If he has wronged you at all, or owes you anything, charge that to my account. I, Paul, write this with my own hand: I will repay it. (Philem. 18–19b)
Paul assumes that both he and Philemon would gladly substitute themselves for each other; it’s how they do life. For that reason, Paul’s request doesn’t seem odd to them.
Since Paul’s letter to the Colossians is read to the church at the same time as his letter to Philemon, Paul’s “off the cuff” remark about “filling up what is lacking in Christ’s afflictions” also makes sense to them. That means that the J-Curve is their normal. The entire congregation sees life as defined by substitutionary love that participates in Christ’s dying and rising. The gospel re-enacted functions at the DNA level for how the church does life.
Here’s my paraphrase of what Paul says:
I know that all of you at Colossae don’t just believe the gospel; you act out the gospel in a life of dying love for one another. Just as Jesus substituted himself for you, so you live a life of substitutionary love. The gospel has radically reshaped your relationships. It’s natural, then, for me to presume Philemon would willingly gift Onesimus to help me; that’s how you do life. But I’m not asking for that. I simply want Philemon to receive Onesimus back not just as a slave, but as a brother.
HEMMED IN ON EVERY SIDE
When I was discovering this in Philemon, our family, but especially Jill, was under enormous pressure. Our six kids, aged three to sixteen, were constantly fighting and whining. Caring for Kim, our fourth child, had depleted our savings; we were living from paycheck to paycheck.
Jill did all her gift buying for the kids at thrift stores, putting the best face on it by packing their presents in boxes from brand-name stores. Our kids figured out what she was doing and started sniffing their stale-smelling presents when they opened the boxes! Then Kim was kicked out of a school because they didn’t think she could learn.
Every area of our life had become extraordinarily difficult—and Jill felt the brunt of it. I didn’t know what to do; I didn’t know how to love her. She was hemmed in on every side. With Philemon in mind, I prayed God would allow me to experience what she was experiencing. I wrote this prayer in my journal in January 1991:
How do I love her?
How do I give myself up for her? How do I die for her?
When I prayed this prayer, I wasn’t sure what it looked like to “give myself up for her.” Over the next few years, God began to show me what that looked like in everyday moments.
Here’s one glimpse. We’d moved to the edge of Philadelphia’s northern suburbs in 1993 to get better schooling for Kim. We had a place that allowed Jill to fulfill her childhood dream of having farm animals. Growing up on the streets of Philly with a concrete backyard, she had longed for some green acres. We had four pygmy goats and one big sheep named Ed.
ED THE SHEEP
In the winter of 1995, our local weather forecasters began predicting the storm of the century. A couple of days before the storm, Jill began worrying about her animals in their little wooden shelters. Since Ed had a six-inch-deep coat of wool, I wasn’t concerned, but I called a local sheep farmer and asked if the animals would be OK. He said yes, as long as they had shelters. I shared this with Jill, and it seemed to calm her.
On Saturday evening, when we already had a foot of snow on the ground, Jill began to get nervous again. We knew the goats were savvy and would go into their sheds, but Ed wasn’t the sharpest tack in the box. I went to bed about 10 p.m. and was drifting off to sleep when I heard Jill’s voice from the next room: “Paul, would you check the sheep? I’m concerned about Ed.” As I lay there, I plotted my response.
I’d remind her of what the farmer had said, then I’d explain the insulating value of snow, not to mention Ed’s thick coat. But I knew Jill well enough to realize that none of this would convince her. She’d just go out into the blizzard by herself, which would just get me more irritated at her.
Then I remembered how Paul re-enacted the gospel. I thought, “This isn’t complicated. I can substitute my warmth for her worry.” The problem wasn’t Ed, but Jill’s anxiety. So I crawled out of bed, put on my boots and jacket, and checked Ed. He was fine, so Jill was too.
In the morning, we trudged out together into a winter wonderland of snow to check on the animals, but especially Ed. As we called his name, we made a poem: “Where is Ed? Is Ed dead? Will he come out of his bed?” Finally, one of the lumps on the field began to move, and out popped Ed!
A NEW VISION OF NORMAL
In this small act of dying, I loved my wife differently. I realized that in Philemon and elsewhere, Paul was re-enacting the gospel, Jesus’s death for us. The word for means the weight of our sins comes on Jesus. Paul uses for when he defines the gospel:
The Lord Jesus Christ . . . gave himself for our sins. (Gal. 1:3a–4b)
Christ died for our sins. (1 Cor. 15:3b)
So just as Jesus substitutes himself for us, we substitute the pieces of our lives for others. Now I understood how Paul could fill up what was lacking in Christ’s afflictions. Jesus’s death was once for all.
His death for Jill was finished—mine was ongoing. I could substitute myself for the pieces of her life, like checking on Ed. So I had a mini-death, and Jill could live. Paul articulates this:
For we who live are always being given over to death for Jesus’ sake, so that the life of Jesus also may be manifested in our mortal flesh. So death is at work in us, but life in you. (2 Cor. 4:11–12)
Here’s the thing: when we understand that substitution is the heart of love, we see life through a different lens. We realize that all of life is love. Love is 24-7.
 The influential scholar Albert Schweitzer called this pattern Paul’s “mysticism.” See The Mysticism of Paul the Apostle, trans. William Montgomery (Baltimore: Johns Hopkins University Press, 1998).
 James D. G. Dunn, The Epistles to the Colossians and to Philemon (Grand Rapids, MI: Eerdmans), 304–5. We have at least one record of a slave running away from his master in Roman times to a potential mediator who appeals on the slave’s behalf by letter.
 See N. T. Wright, Paul and the Faithfulness of God (Minneapolis: Fortress, 2013) 12–15.
 Mary Beard mentions two slave prices in Pompeii: 1,500 and 6,252 sesterces (one quarter of a denarius). Pompeii: The Life of a Roman Town (London: Profile Books, 2008), 179. A denarius would be worth about $100 (Matt. 20:2) in modern terms, showing that slaves could be very costly.
 Jimmy Agan in personal correspondence.
 Richard B. Gaffin Jr. writes about Col. 1:24, “This union is such that not only can the sufferings of believers be viewed as Christ’s and as being conformed to his death, but also the personal, past-historical sufferings of Christ and the present afflictions of the church are seen together as constituting one whole. Again, certainly not in the sense that the sufferings of the church have some additive atoning, reconciling value.” “The Usefulness of the Cross,” Westminster Theological Journal 41, no. 2 (Spring 1979): 242. See also John Murray, The Epistle to the Romans (Grand Rapids, MI: Eerdmans, 1959), 299.
Content taken from J-Curve by Paul E. Miller, ©2019. Used by permission of Crossway, a publishing ministry of Good News Publishers, Wheaton, Il 60187, www.crossway.org.
Paul E. Miller (MDiv, Biblical Seminary) is the executive director of seeJesus as well as the best-selling author of A Praying Life and several other books. With the help of his ministry staff, Miller creates and conducts interactive discipleship seminars throughout the world. He and his wife, Jill, live in the Philadelphia area and have six children as well as a growing number of grandchildren.