Your question is not clear. Are you asking if the majority of people will go to Hell? And that the reason for that is that the majority of people do not believe in God? Or are you asking if the reason that if even only 1 or 2 people go to Hell, will it be for their lack of belief in God? In Matthew 25:31-46, Jesus says that if someone goes to Hell it will be because they did not help the "least of their brothers". In those scriptures Jesus doesn't say anything about belief, only about what a person does. Of course, if a person believes that there is a God, and believes that the Bible is the "Word of God", and believes that Jesus is the Son of God, then, he may be more likely to read what Jesus says in Matthew 25:31-46 is the real criteria that determines whether he goes to Heaven or Hell ! That is, of course, if the person believes that Jesus knows more than his Liberal Minister who says that it doesn't matter what we do on Earth, only what we believe or have Faith in.