I've heard so many testimonies and as I reflect on my own, there is no way those people or myself could of cleaned ourselves up. Once God quickens the heart and mind, that person's actions, thoughts, world view, thoughts on sin realized, and their affection for God, His Word and other believers radically changes. When God saves a person, He changes that person more and more in to His image. That is the miracle of salvation.
"And you were dead in the trespasses and sins in which you once walked, following the course of this world, following the prince of the power of the air, the spirit that is now at work in the sons of disobedience— among whom we all once lived in the passions of our flesh, carrying out the desires of the body and the mind, and were by nature children of wrath, like the rest of mankind. But God, being rich in mercy, because of the great love with which He loved us, even when we were dead in our trespasses, made us alive together with Christ—by grace you have been saved..." Ephesians 2:1-5
When we think of evangelism, we must think of ourselves as Ezekiels who stand in a valley of dry, dead bones. You can't get a better image of dead people than that! There is no way we could manipulate someone to Christ because they are really dead in their sin. I get chills whenever I read this powerful text.
"The hand of the Lord was upon me, and he brought me out in the Spirit of the Lord and set me down in the middle of the valley; it was full of bones. And he led me around among them, and behold, there were very many on the surface of the valley, and behold, they were very dry. And he said to me, “Son of man, can these bones live?” And I answered, “O Lord God, you know.” Then he said to me, “Prophesy over these bones, and say to them, O dry bones, hear the word of the Lord. Thus says the Lord God to these bones: Behold, I will cause breath[b] to enter you, and you shall live. And I will lay sinews upon you, and will cause flesh to come upon you, and cover you with skin, and put breath in you, and you shall live, and you shall know that I am the Lord.”
So I prophesied as I was commanded. And as I prophesied, there was a sound, and behold, a rattling, and the bones came together, bone to its bone. And I looked, and behold, there were sinews on them, and flesh had come upon them, and skin had covered them. But there was no breath in them. Then he said to me, “Prophesy to the breath; prophesy, son of man, and say to the breath, Thus says the Lord God: Come from the four winds, O breath, and breathe on these slain, that they may live.” So I prophesied as he commanded me, and the breath came into them, and they lived and stood on their feet, an exceedingly great army."This is a great little video with this passage.