John 3:36 He that believeth on the Son hath everlasting life: and he that believeth not the Son shall not see life; but the wrath of God abideth on him.
The context of this verse is important. John the Baptist had just informed his disciples that Jesus had been given the authority over all things in heaven and earth. Opposing Him is foolish and futile. Everyone should follow Him... believing.
John boldly confronted people about unbelief and its consequences. He did so without coercion or force, just words... truth. Truth so simple and clear that they could not claim they had never heard, or did not understand. They were faced with either believing the Gospel, or not believing.
John's message is clear. There is a single belief, Gospel faith, which frees a person from the abiding wrath of God. Based on what John said here, the eternal affects of Gospel faith, or lack of faith, exist in the present. John taught that the wrath of God actually lives with unbelievers waiting to be permanently released into their existence. But for those who believe, their endless life in Jesus Christ has already begun.
As far as we know, there were no atheists standing there listening to John. These were religious people, but this wasn't about religion. It was about their belief concerning Jesus and His Gospel. These words openly communicate John's belief that religious people can be people without Gospel faith. Religious but lost. We must make sure we know Jesus and believe His Gospel. Nothing else, in the context of eternity, really matters.