He who conceals his sins will not prosper, but whoever confesses and renounces them will find mercy. -Proverbs 28:13

(T)hat man is destitute of true holiness who can look back upon his own past sin without sorrow. Oh, to think of our past lives! There were some of us who knew the Lord at fifteen years of age, but those fifteen years of unregeneracy – we can never forget them! Others may say, “We did not know Him till we were fifty or sixty.” Ah, my dear brethren! you have much to weep over, but so have those of us who knew the Lord in early life. I can look back upon God’s mercy with delight, but I hope I shall never be able to look back upon my sins with complacency. Whenever a man looks to any of his past faults and shortcomings, it ought to be through his tears. Some men recall their past lives, and talk of their old sins, and seem to roll them under their tongues as a sweet morsel. They live their sins over again. As it was said of Alexander –

“He fought his battles o’er again,
And twice he slew the slain.”

There are those who revel in the memory of their iniquities. They live their life in imagination over again. They recollect some deed of lewdness, or some act of infamy; and, as they think it over, they dare not repeat it, for their profession would be spoiled; but they love the thought, and cultivate it with a vicious zest. Thou are no friend to true holiness, but an utter stranger to it unless the past causes thee profound sorrow, and sends thee to thy knees to weep and hope that God, for Christ’s sake, has blotted it out. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/2902.cfm