Not everyone believes the promise of life the first time he hears it.
Some people are so committed to salvation by works that they think the promise of eternal life is ridiculous.
Before such a person will believe, he will probably have to go through a process of conviction first. He will need to be convinced of his total inability to earn salvation based on his good behavior before he will believe that salvation is by faith apart from works (Eph 2:8-9). I had to go through that before the message of justification by faith apart from works made sense to me (cf. Gal 2:16).
But it’s one thing to recognize that an individual needs to be convicted of his sin before he’ll be ready to believe the gospel and another thing to say no one can believe in Jesus for eternal life without going through a long preparation of conviction and dealing with his or her sinfulness first.
The idea that you have to go through several steps of conviction and remorse and repentance before you can believe is called “preparationism.”
C. F. W. Walther (1811-1887)was a German-speaking American Lutheran theologian. I’m reading his book Law & Gospel: How to Read and Apply the Bible for the third time. He wrote in the 19th century, when many revivalists evangelized people by telling them they had to go through a time of preparation before they could come to Christ in faith. This is what Walther had to say about that message:
Is it not horrible to tell people who have learned by experience that they are poor, lost sinners and are still stuck in sin that—even though God has indeed redeemed them—they still have to do much before they will be allowed to believe and be redeemed? According to this horrible teaching, sinners want to share with God in the work of their redemption. That is nothing short of blasphemy” (Walther, Law & Gospel, p. 421).
There is nothing the sinner needs to do before believing. As we might say today, unbelievers have a “Son problem, not a sin problem.” That is, they don’t need to deal with their sins before coming to faith. They can believe in Jesus right away. When Jesus evangelized the woman at the well, He didn’t tell her to leave her live-in-boyfriend before taking a drink of the water of life (John 4:13-14).