Good question

Roy. You stated "an atheist can go heaven but he can also go to hell, and a Christan can go to heaven but he can also go to hell, how can that be?" Roy, that's a good question Roy and one that needs to be examined according to Scripture and not the teachings of man. Well, if what your referring to is what happens when one dies, then what you have stated is somewhat strange to understand. However, if one examines the Bible more closely, a correct understanding it will be had in this matter.

First, consider John 3:13. where it is stated "No one has ever gone into heaven except the one who came from heaven--the Son of Man." (NIV). Here the Bible is very clear about going to Heaven after one dies. No one except Jesus has had this experience. Then we must consider what we have done while here on earth during our lifetime. It is unrealistic to believe that unrighteous individuals would be welcomed into Heaven! What has any individual done in their lifetime to warrant their entrance into Heaven upon their death? The Bible is quite clear on the condition of the human race. It gives us insight of ourselves when we read Ro 3:23 "for all have sinned and fall short of the glory of God." Notice here Roy that there is no exception made .....all is all, all have sinned and have no standing in God's glory at the present time. This is further strengthened when Ro 3:10 is examined. Here it states: "As it is written: "There is no one righteous, not even one." If none are righteous then how can it be that the unrighteous person can be welcomed into heaven?

What then do we find in the Bible concerning our fate? Romans 6:10 "For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord." We are all sinners, all of us have fallen short of the mark of perfection. We are imperfect in our ways. We are sentenced to the condition of death not to a future of torment. We can find proof of this in Eccl. 9:10 where it states "Whatever your hand finds to do, do it with all your might, for in the grave, where you are going, there is neither working nor planning nor knowledge nor wisdom."
Note here that there is neither working nor planning nor knowledge nor wisdom after death, just burial in the grave!

Why would there be the opportunity to ascend into Heaven upon death? Would this not make the Ransom sacrifice on the cross a needless thing, bypassing the need for the Ransom Sacrificeand its being applied on behalf of all mankind? Consider Acts 3:21: "Whom the heaven must receive until the times of restitution of all things, which God hath spoken by the mouth of all his holy prophets since the world began." Why would this verse in Acts 3:21 mention "the times of restitution" if all have been transported to Heaven or assigned to Hell?
Food for thought Roy!

Bro. Harold