For with the heart man believeth unto righteousness; and with the mouth confession is made unto salvation. -Romans 10:10

“But,” I hear someone say, “it is impossible; I have tried it, and I have broken down; I did try to get better, but I did not succeed; it is of no use, it cannot be done.” You are right, my dear friend, and you are wrong. You are right, it is of no use going about it as you did; if you went in your own strength, holiness is a thing you cannot get, it is beyond you. The depth says, “It is not in me;” and the height saith, “It is not in me.” You can no more make yourself holy than you could create a world. But you are wrong to despair, for Christ can do it; He can do it for you, and He can do it now. Believe on Him, and that believing will be the proof that He is working in you. Trust Him, and He that has suffered for thy sins, the Lion of the tribe of Judah, shall come in, and put to rout the lion of the pit. He will bruise Satan under thy feet shortly. There is no corruption too strong for Him to overcome, there is no habit too firm for Him to break. He can turn a lion to a lamb, and a raven to a dove. Trust Him to save thee, and He will do it, whosoever thou mayest be, and whatsoever thy past life may have been. “He that believeth and is baptized shall be saved;”-that is, he shall be saved from his sins, and delivered from his evil practices; he shall be made a new man in Christ Jesus by the power of the Spirit, received through the medium of his faith. Believe, poor soul, that Christ is able to save thee, and He will do it. He will be as good as thy faith, and as good as His own word. May He now add His own blessing to the word I have spoken, and to the people who have heard it, for His own sake! Amen. ~ C.H. Spurgeon

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