Restore to me the joy of your salvation, and uphold me with a willing spirit.
These are words of David from Psalm 51 that are well known. In fact, we sing them in at least one of our songs, if not more. It is important to understand what it is that David is asking for in this petition, especially as it compares to what we often ask in petition to God. It is not unusual for us to pray that God forgive us of the sin that we have in our lives. This is a good thing for us to do, and we should continue to do so. Yet David goes beyond simply asking God for forgiveness— David asks God to also change the person that David is in order that he might be more pleasing to God. David understands that “the joy of [God’s] salvation” is not found only in the knowledge that we have been forgiven, as wonderful as that is. But David understands that true joy is borne primarily out of being a person whom God is transforming into His likeness. It is in the willingness to follow after God, and to allow God to continually change and renew us, that we begin to experience the joy of his salvation that he has granted us in Jesus Christ.
In Ephesians 4 Paul writes of the truth that is in Jesus, and talks about those who are in him putting off “the old self.” By doing that— corroborating David’s understanding—Paul says we will “be renewed in the spirit of [our] minds . . . created after the likeness of God in true righteousness and holiness.” That is the joy of God’s salvation.