Jesus told the story of the shepherd who left the 99 in order to pursue the one sheep who had strayed. Throughout the church, pastors—who are shepherds—have had to carefully balance these tasks. When they miss the biblical balance in this, some act as through there is no such thing as straying. They don’t really pursue those who wander. But others are so scrupulous that they preach every Sunday as though the 99 had wandered off. The 99 are not so much in danger from wolves as they are in danger of another hectoring lecture about wolves.
There has to be balance. God’s people need to hear the gospel regularly, that they might be encouraged. But they should not hear it declared as though all of them are somehow nurturing an evil heart of unbelief. But neither should they hear it as though unbelief and wandering are absolute impossibilities.
Fortunately, the same word can encourage the 99 and retrieve the one. And here it is. Here is the mystery. God was in Christ, reconciling the world to Himself. He was in Christ doing this in the cross, which is where Jesus completely identified Himself with our sin. That is the proclamation. There is also an accompanying appeal—be reconciled to God.
Here is the staggering exchange that is offered. Jesus stands before you and says that He has no sin, and invites you to become His sin. Jesus stands before you and says that you have no righteousness, and offers to become your righteousness—as an absolute gift of free grace. You become His sin and He becomes your righteousness. That offer is before you now, and that is good news.