For the good that I would I do not: but the evil which I would not, that I do….O wretched man that I am! who shall deliver me from the body of this death? I thank God through Jesus Christ our Lord. – Romans 7:19, 24-25

You ask, “What if a child of God should fall into sin?” I answer, the child of God does fall into sin; every day he mourns and groans because when he would do good, evil is present with him. But though he falls into sins, he is not condemned for all that-not by one of them, or by all of them put together, because his acceptance does not depend upon himself, but upon the perfect righteousness of Christ; and that perfect righteousness is not invalidated by any sins of his. He is perfect in Christ; and until Christ is imperfect, the imperfections of the creature do not mar the justification of the believer in the sight of God. But oh! if he fall into some glaring sin,-O God, keep us from it!-if he fall into some glaring sin, he shall go with broken bones, but he shall reach heaven for all that. Though, in order to try him and let him see his vileness, he be suffered to go far astray, yet He that bought him will not lose him; He that chose him will not cast him away; He will say unto him, “I, even I, am He that blotteth out thy transgressions for Mine own sake, and will not remember thy sins.” David may go never so far away, but David is not lost. He comes back and he cries, “Have mercy upon me, O God!” And so shall it be with every believing soul-Christ shall bring him back.

If I have been speaking to a backslider, I pray he will not make a bad use of what I have said. Let me say to him, “Poor backslider! thy Father’s bowels yearn over thee; He has not erased thy name out of the registry. Come back, come back now to Him and say, ‘Receive me graciously, and love me freely’; and He will say, ‘I will put you among the children.’ He will pass by your backsliding and will heal your iniquities; and you shall yet stand once more in His favour, and know yourself to be still accepted in the Redeemer’s righteousness and saved by His blood.” ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0362.cfm