Repentance is a gift of God. Peter rejoiced that God gave repentance to Israel (Acts 5:31) and later the apostles rejoiced that God granted repentance to the Gentiles (Acts 11:18). God sovereignly lets us see sin in its ugliness and gives us a heart to hate it and leave it. That is a gift.
Repentance is a discipline. You can get better at it, and the more mature you are, the less the time you’ll need between sinning and then acknowledging and turning from that sin.
Repentance is a blessing. If sin is what separates us from God–and it is, if sin is what spoils our consciences–and it is, if sin is what stops up the flow of joy–and it is, then repenting from sin belongs with reconciliation, cleansing, and a renewed spirit.
Every Lord’s Day we are brought to reckon with our need for repentance. The battle to mortify our sin is not finished, even though Christ’s sacrifice to atone for our sin is. As part of our worship we acknowledge that we, in our flesh, are powerless against sin, but that when we call on the Lord we will be saved.
It may be hard to rank the most important or necessary part of our liturgy. But our confession of sin belongs as part of our worship, and ought to be part of our walk.
Martin Luther captured this in the first of his 95 Theses:
When our Lord and Master Jesus Christ said “Repent,” he intended that the entire life of believers should be repentance.
To the Laodiceans, the Amen, said:
Those whom I love, I reprove and discipline, so be zealous and repent. (Revelation 3:19)