Genesis 3:22-24 And the Lord God said, Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever: Therefore the Lord God sent him forth from the garden of Eden, to till the ground from whence he was taken. So he drove out the man; and he placed at the east of the garden of Eden Cherubims, and a flaming sword which turned every way, to keep the way of the tree of life.
To get back into the Garden of Eden (to get to eternal Heaven), we must get past a flaming sword. A sword cuts, and a flame destroys. To get to Heaven our flesh is cut away and destroyed. The clues pointing to Separation Atonement are everywhere in the Bible.
Isaiah 66:16 For by fire and by His sword The Lord will judge all flesh; And the slain of the Lord shall be many.
Here again there is a sword to cut the flesh, and a fire to destroy it.
1 Corinthians 5:5 deliver such a one to Satan for the destruction of the flesh, that his spirit may be saved in the day of the Lord Jesus.
In this passage, a person who is engaged in wickedness must be removed from the church. He is cast out to be judged under temporal judgement. It is hoped that his spirit may be saved on the Day of Judgement.
John 6:63 It is the Spirit who gives life; the flesh profits nothing. The words that I speak to you are spirit, and they are life.
There is so much text in the Bible speaking favorable of the spirit, and negatively of the flesh. Separation atonement should be a common topic, but almost no one ever heard of it.
