The LORD God declares He Himself will shepherd His sheep. He will seek them out. He will rescue them. He will save. He will gather them in. In other words, the Good Shepherd will take care of His own sheep.
The heart of your sermon is the promise that God, in Jesus, has sought and found each of us. He receives us sinners and invites us to eat with Him at His table.
This is why Paul is still an “example” for us. If this is what God in Christ can do with “a blasphemer, a persecutor, and a man of violence," imagine what God in Christ can do with you and me.
All of this is interesting and useful in preparing a sermon, however, there are no explicit words of Gospel in this text. How does one preach without shoe-horning the Gospel into the message, perhaps in an inappropriate or confusing manner?