The Wandering Sheep, the Work of Salvation, and the Watchful Shepherd
Peter reminds his audience of the gospel in the middle of this passage about their conduct. The gospel is not just for non-Christians but for the believer. This is the basis on which they are able to serve Christ even in the midst of difficulties. We are like wandering sheep but there is a work of salvation by the watchful Shepherd. He intimately knows His sheep, comforts them and provides for them, feeding them with His Word.
A video of the full service can be viewed here.