And the son said unto him, Father, I have sinned against heaven, and in thy sight, and am no more worthy to be called thy son. But the father said to his servants, Bring forth the best robe, and put it on him; and put a ring on his hand, and shoes on his feet: And bring hither the fatted calf, and kill it; and let us eat, and be merry: For this my son was dead, and is alive again; he was lost, and is found. – Luke 15:21-24

The prodigal had many sins to confess; but before he came to the details of them, his father had forgiven him. I love confession of sin after forgiveness. Some suppose that after we are forgiven we are never to confess; but, oh, beloved, it is then that we confess most truly, because we know the guilt of sin most really! Then do we plaintively sing-

“My sins, my sins, my Saviour,
How sad on Thee they fall!
Seen through Thy gentle patience,
I tenfold feel them all,
I know they are forgiven,
But still their pain to me
Is all the grief and anguish
They laid, my Lord, on Thee.”

To think that Christ should have washed me from my sins in His own blood, makes me feel my sin the more keenly, and confess it the more humbly before God. The picture of this prodigal is marvelously true to the experience of those who return to God. His father kissed him with the kiss of forgiveness; and yet, after that, the young man went on to say, “Father, I have sinned against heaven, and before thee, and am no more worthy to be called thy son.” Do not hesitate, then, to acknowledge your sin to God, even though you know that in Christ it is all put away. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/2236.cfm