Let the wicked forsake his way, and the unrighteous man his thoughts: and let him return unto the LORD, and He will have mercy upon him; and to our God, for He will abundantly pardon. – Isaiah 55:7

It is possible, dear friends, that your opposition to Jesus Christ has taken the form of the love of a favourite sin. Now, there is nothing more certain than this, that you cannot be saved and keep your sins: they must be parted with. No man can carry fire in his bosom and yet be safe from burning. While you drink the poison, it must and will work death in you. The thief cannot expect mercy while he keeps the goods he has stolen…Most men in their heart of hearts would like to have their sins and go to heaven too. But that cannot be; while God is just, and heaven is holy, and truth is precious, it cannot be. What then? “Let the wicked forsake his way, and the unrighteous man his thoughts: and let him return unto the Lord, and He will have mercy upon him; and to our God, for He will abundantly pardon.” Give up, give up; give up your sin…The sins of the flesh are a deep ditch, and the abhorred of the Lord fall therein; but as thou lovest thy soul, O young man, escape like a bird from the fowler’s snare. Here is the message of God to thee: “Give up, give up thy sin.” Perhaps though you hear the summons, you trifle with it, and reply, “Yes; I mean to give them all up, and I hope by so doing I shall find my way to heaven. I shall deserve well of my Maker when I have denied myself all sinful pleasures.” But stop; let me not deceive you: this is not all. I fear that some men are not improved in their hearts when they are altered in their outward behavior. I am glad of the outward improvement, but I have sometimes fancied that they have only changed their sins but not given them up. They show no leprosy in their skin, but it lies in their bone and their flesh. It is little use merely to shift the region in which sin sets up its throne if its dominion is still undestroyed…All sin must be cast out of the throne of the heart, and whatever righteousness that is not Christ’s righteousness must go with it. I would fain put the sword-point to thy heart, O sinner, and say, “Give up all that opposes Christ;” for if thou do not give it up, thy soul will be lost. ~ C.H. Spurgeon

https://www.blueletterbible.org/comm/spurgeon_charles/sermons/1007.cfm