The short answer is that scripture teaches it:

1 Corinthians 2:14

“The natural person does not accept the things of the Spirit of God, for they are folly to him, and he is not able to understand them because they are spiritually discerned.” (1 Cor 2:14)

A natural person, one born of flesh only, is incapable of understanding that which is spiritually understood. Salvation (repenting and believing the gospel) is a spiritual transaction that requires spiritual understanding, for which regeneration is an absolute requirement.

Romans 8:7-8

”For the mind that is set on the flesh is hostile to God, for it does not submit to God’s law; indeed, it cannot. ⁸ Those who are in the flesh cannot please God.” (Rom 8:7-8)

A mind can be fleshly (carnal), spiritual, or in the case of believers, in whom sin still resides, BOTH carnal and spiritual. The unbeliever is controlled by a fleshly mind and cannot please God. True repentance and belief in Christ pleases God, Therefore spiritual regenerating must precede faith.

Ephesians 2:1-5

“And you were dead in the trespasses and sins ² 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— ³ among whom we all once lived in the passions of our flesh, carrying out the desires of the body^[a] and the mind, and were by nature children of wrath, like the rest of mankind.^{[b] 4} But^[c] God, being rich in mercy, because of the great love with which he loved us, ⁵ even when we were dead in our trespasses, made us alive together with Christ—by grace you have been saved—” (Eph 2:1-5)

What can a ‘dead’ man do? WHEN WE WERE DEAD, we who now believe were made alive in Christ. That’s the very definition of ‘regeneration’.

2 Corinthians 4:1-4

“Therefore, having this ministry by the mercy of God,^[a] we do not lose heart. ² But we have renounced disgraceful, underhanded ways. We refuse to practice^[b] cunning or to tamper with God’s word, but by the open statement of the truth we would commend ourselves to everyone’s conscience in the sight of God. ³ And even if our gospel is veiled, it is veiled to those who are perishing. ⁴ In their case the god of this world has blinded the minds of the unbelievers, to keep them from seeing the light of the gospel of the glory of Christ, who is the image of God.”

Who is perishing? All who have not received and believed in Christ. Why have they NOT received and believed in Christ? Their minds have been blinded by the god of this world. Regeneration opens blind minds and necessarily precedes faith.

John 1:12-13

”But to all who did receive him, who believed in his name, he gave the right to become children of God, ¹³ who were born, not of blood nor of the will of the flesh nor of the will of man, but of God.” (John 1:12-13)

The children of God are those who receive Christ and believe in his name. Those who receive and believe in Christ are those born of God, not by any form of human desire or will. To be born of God is to be regenerated. Note that no one is regenerated by an act of human will.

John 3:3

”Jesus answered him, “Truly, truly, I say to you, unless one is born again he cannot see the kingdom of God.””

To ‘see’ the kingdom of God in the above passage means “to perceive” Just as we must have been born naturally to physically see, we must be born spiritually (regenerated) to spiritually see.

Those who believe that human faith precedes regeneration generally fall into two groups:

• We are all ‘naturally’ capable, without divine assistance, to make a genuine decision for Christ, by an act of human free will.
• While we aren’t ‘naturally’ capable of such a decision, God, by an act of ‘prevenient grace’, grants the ability to make a free will decision to accept Christ, and then be ‘regenerated’.

I believe the above passages refute the first proposition, on its face. I also believe the second proposition to be in error simply because prevenient grace, in the Wesleyan sense is nowhere taught in the Bible. The thought is that God bestows prevenient grace to the lost sinner, who is then able to consider the claims of the gospel message and either freely accept or reject them by an act of natural human will.

Additionally, I can find NO language in all of the Bible that discusses some sort of decision making process in the process of the salvation of men. Even IF true and a human free will decision determined the eternal destiny of anyone, that person will have saved himself/herself, although God made it possible to be saved through the death of Christ.

It is my belief, based on the above passages, that the human will must ‘itself’ be changed for the natural man to desire to repent of sin and believe in Christ.

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NOTE: For more in-depth discussions concerning ‘Prevenient Grace’ See:

1. Does Scripture Teach Prevenient Grace n the Wesleyan Sense?

2. Is Prevenient Grace in the Bible?

3. What is Prevenient Grace?