Do not grieve the Holy Spirit of God, by whom you were sealed for the day of redemption.
   - Ephesians 4:30

God's judgment of the believer's sins is not less than that of the unbeliever's sins. When a believer sins, the question of criminality cannot be raised against him, for the Judge settled that on the cross; but the question of communion [that is, an unhindered relationship with God] is raised within the believer by the Holy Spirit every time He is grieved.

On a clear, moonlit night, a man, looking at the moon's reflection in a still pool, remarks how beautiful the moon is. Then someone throws a stone into the pool, and the man exclaims, "The moon is all broken up and the fragments are shaking in disorder!" His friend replies, "Look up, man. The moon hasn't changed. The condition of the pool has changed."

Your heart is the pool. When you don't allow evil in your life, the Holy Spirit reveals the glories of Christ for your joy. But the moment sin enters, the Holy Spirit begins to disturb the pool and your happy experiences are broken up. You are restless and disturbed within. But when you confess the sin, the calm, sweet joy of communion is restored.

While your heart is in the state of unrest, has Christ's work changed? No! Then your salvation hasn't changed, either. Has God's Word changed? No! Then the certainty of your salvation also hasn't changed. What has changed? The Holy Spirit's action in you. Instead of filling your heart with the sense of Christ's worthiness, He is grieved at having to fill you with the sense of your sin. He takes away your joy until you judge and resist the evil that grieves Him. This done, He restores your communion.

G. Cutting