That as sin hath reigned unto death, even so might grace reign through righteousness unto eternal life by Jesus Christ our Lord. – Romans 5:21

Men, after they are converted, and begin to examine themselves in the light of God’s Word, if they are at all like us, find sin everywhere within them;-sin in the affections, so that the hearts lusteth after evil things;-sin in the judgment, so that it often makes most serious mistakes, and honestly puts bitter for sweet, and sweet for bitter-sin in the desires, so that though we try to curb them, they wander hither and thither, whither we would not; sin in the will… that he is still very proud, and wants to have his own way,-and is not willing to bow submissively to the will of God; sin in the memory, so that the most godly people can often recollect a snatch of a bad old song which they used to hear or to sing, far more readily than they can remember a text of Scripture; which they wish to treasure up in their memories, for memory has become unhinged, like all the rest of our faculties, and is quick to retain evil, and slow to retain that which is good. Brethren and sisters in Christ, in what part of our body does sin not dwell? Is there any single faculty, or power, or propensity that we have which will not lead us astray if we will let it do so? Are we not obliged to be always upon our guard against ourselves, and to watch ourselves as a garrison of soldiers would have to watch the natives of a country whom they had subdued, but who were anxious to throw off the yoke of the foreigners who had overcome them. In a similar fashion, grace is a foreigner in possession of our nature, and it holds by its own superior force what it has won; and only by its supernatural strength are we kept from regaining our former position.

Thus you see how sin abounds, even in the heart of a believer; but, blessed be God, grace doth much more abound there; for, although the will is still strong, there is a higher power that subdues and controls it so that our will is being gradually conformed to the will of God. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/3115.cfm