Excerpt:
Peter is saying that suffering comes for two reasons. The first reason is for sanctification. To set us apart to live for the will of God rather than the desires of men. And after sanctification, the second reason is sufficient time. Now that you are saved you have had enough time in the past to live for and exercise the flesh. The moment you receive Christ God considers you have had enough time. It is like a parent coming to a child and saying, "Time to grow up." You have had sufficient time of your life to work out the will of the heathen in doing all of these things. It is over. It is past. Time to spiritually decide that the Lord has set you apart for Himself. Stop trying to reach back into the past, even stop trying to reach into future, but follow Christ.
Additional Information:
covers I Peter 4:2-6