John 15 records some of Jesus' last essential instructions for his closest circle of friends before He went to the cross. Jesus uses the metaphor of the grafting process a gardener uses in a vineyard or nursery. It is apparent that this process involves considerable effort and pain. The effort and pain produce the result of increased productivity. The spiritual corollary is well described by John Bunyan when he wrote:
Conversion is not the smooth, easy-going process some men seem to think. It is wounding work, this breaking of the hearts; but without wounding there is no saving... Where there is grafting there is a cutting, the [thin, young branch] must be let in with a wound; to stick it onto the outside or tie it on with a string would be of no use. Heart must be set to heart and back to back, or there will be no sap from root to branch, and this I say, must be done by a wound.
Joni Eareckson Tada wrote in her blog shortly after her cancer diagnosis:
The diving accident in which I became paralyzed ... would force my wound to his wound, my heart to his heart. ... the wounding is where divine sap flows and spiritual fruit blossoms. In affliction and suffering, our hearts are pressed into his. And the life of God flows into us, wound to wound. In those times of brokenness, remember that in Christ, the result is life, life, and more life.
Help me, Lord, to remain, to abide in you this day, no matter what my circumstances. (Joni, Joni's Corner, Joni and Friends, 7/27/2010)
It is upside down thinking but no less true: Our hearts REQUIRE wounding to be both productive and whole! For myself, I prefer "Jesus wounds" - my heart to His!