To believing, there must be a clear conviction of sin, and the merits of the blood of Christ, and of Christ’s willingness to save upon this consideration, namely, that you are a sinner; things all harder than to make a world. All the power in nature cannot get up so high in a storm of sin and guilt as really to believe there is any grace, any willingness in Christ to save. When Satan charges sin upon the conscience, then for the soul to charge it upon Christ, that is gospel-like; that is to make Him Christ. He serves for that use, to accept Christ’s righteousness alone. His blood alone for salvation, that is the sum of the gospel. When the soul, in all duties and distress, can say, “Nothing but Christ, Christ alone, for righteousness, justification, sanctification, redemption,” (I Cor 1:30); not humblings, not duties, not graces; that soul has got above the reach of the billows. Thomas Willcox
A true belief in Christ alone by grace alone is something that cannot be worked up by human effort and human nature. It is completely beyond the powers and abilities of the natural man, though it seems so easy to the unsuspecting and the untaught in the modern day (and all other periods as well). It seems so easy to believe something as long as one has the facts and is willing to believe the facts, but that is because the darkened mind is unaware of the darkness it lives in not to mention the absolute inability it has in the spiritual realm. The Scripture sets out that faith is the work of God and is an incredible act of His power. If the human heart could grasp the fact that it takes the same strength to believe that it took to raise Christ from the dead, it would see its own inability to perform such a great act.
Ephesians 1:18 I pray that the eyes of your heart may be enlightened, so that you will know what is the hope of His calling, what are the riches of the glory of His inheritance in the saints, 19 and what is the surpassing greatness of His power toward us who believe. These are in accordance with the working of the strength of His might 20 which He brought about in Christ, when He raised Him from the dead and seated Him at His right hand in the heavenly places.
One aspect of faith, or perhaps the way to clear the path to faith, is that of the conviction of sin. Christ came to save sinners and He is a Physician that will only deal with sinners. Until a person knows that s/he is a sinner, and even such a vile and helpless sinner that s/he cannot deal with sin in the power and strength of self, that person will not look to Christ alone as Savior. It is vital, then, for a person not just to be aware that s/he is a sinner and think of that as conviction, but for a person to know from the depths of the soul that s/he is a sinner and one that is a sinner by nature and that cannot be dealt with other than by Christ and Christ alone. Sinners must see that their sin is not just what they do, but what they are. Sinners must see that their sin is in their motives, desires, attitudes, loves, and intents. Sinners must see that they do nothing good and that the very best that they can do is evil. Sinners must see that they have no righteousness and nothing but unrighteousness. Sinners must see that sin has made them utterly unable to please God or do one thing that is anything less than sinful.
Part of the work of the Spirit in drawing sinners to Christ is to convince and convict them of sin (John 16:8). While anyone can see that certain things are wrong, it is the work of the Spirit to convince people of the sinfulness of sin in the spiritual realm. As one can do outward good works in the eyes of men and yet in the spiritual realm those things are nothing but sin and self-righteousness, so one can see sin only through external eyes but miss what they really are in the spiritual realm. The words of men in pointing out sin can only reach the externals and never open the eyes that are fast asleep in darkness, but the Holy Spirit can shine the Light into their eyes and make them see the true nature of sin. Until this happens, men will only see their need of a small savior rather than the Lord Jesus Christ as THE Savior of sinners.
It is not just that men must see that they do things that are wrong, but they need to see that THEY are wrong. It is not just that they need to see that they have done some bad things, but that nothing they do can be acceptable to a thrice holy God. It is not just that they need to see that they have some demerit and some merit, but that all they have is demerit. It is not just that they need to see that they cannot please God completely, but that they are totally unable to please God at all. This is to say that the Spirit alone can convince men and convict them that they need a real and complete Savior. Until then, men will continue to think of themselves as basically good and they only need a partial Savior.