To come to Christ for life is for the sinner to abandon his own righteousness and be ready to be made the righteousness of God in Christ.
Knowing this, is the sinner willing to take such an attitude before God on his own? No, because in the first place he does not realize the danger of his situation and is not really deeply heartsick to escape. Instead, people are for the most part at ease with themselves; and if it were not for the Holy Spirit setting off alarms in their conscience or divine intervention, they overwhelmingly choose any other refuge but Christ. In the second place, they will not acknowledge that all their righteousness is as filthy rags, but like the Pharisee with thank God that are not as the publican. In the third place, they are not ready to receive Christ as their Lord and Savior for they are unwilling to part with their idols. They would rather gamble on their soul’s eternal welfare that give their idols up. That is why we say that left to himself, the natural man is so depraved in his heart that he cannot come to Christ.
The Sovereignty of God, A. W. Pink, page 166