Those whom I love I rebuke and discipline. So be earnest and repent.20 Here I am! I stand at the door and knock. If anyone hears my voice and opens the door, I will come in and eat with that person, and they with me. (Revelation 3:19-20 NIV)
Jesus does not want the church of Laodicea to be discouraged by His rebuke–but He definitely wants them to change. Verse 19 contains both an encouragement and a subtle threat.
It is an encouragement because they are to see Jesus’ “rebuke and discipline” as a sign of His love for them. They may very well be true believers, in which case Jesus is using His “rod and staff” to keep them out of trouble and on the right path (Psalm 23:4).
Yet it contains a threat in its subtle implications about what will happen to them if they do not repent. In that case they might not just be rebuked and disciplined, but punished perpetually in hell for disbelief and hardness of heart, because they never really were Christians in the first place. There is a great difference between discipline and punishment. Punishment is a complete payment for sin, which is always extremely severe. But for those who repent, Jesus might choose to only discipline them, which means to give them milder consequences that serve only to remind them to stay away from sin, but not to completely pay them as the deserve for past sins. True Christians will not be punished by God, but we will be disciplined and rebuked.