What is the difference, if any, between Sheol and purgatory?
The doctrine of purgatory is a predominantly Catholic church doctrine:
“Purgatory (Lat., "purgare", to make clean, to purify) in accordance with Catholic teaching is a place or condition of temporal punishment for those who, departing this life in God's grace, are, not entirely free from venial faults, or have not fully paid the satisfaction due to their transgressions.”1
According to Catholicism, punishment for sins still awaits deceased believers:
“That temporal punishment is due to sin, even after the sin itself has been pardoned by God, is clearly the teaching of Scripture.”2
Purgatory is seen as purifying a person of any uncleanness to make them acceptable for eternal life in God’s holy presence.
This is NOT the same as the realm of the dead (Hebrew: Sheol; Greek: Hades), which is reserved for those awaiting God’s Final Judgment, whose names are not written in the Lamb’s Book of Life:
Rev. 20:11-15 Then I saw a great white throne and him who was seated on it …and death and Hades gave up the dead that were in them, and each person was judged according to what he had done. Then death and Hades were thrown into the lake of fire. The lake of fire is the second death. If anyone’s name was not found written in the book of life, he was thrown into the lake of fire.
There are two principal Scripture references used to defend the teaching of purgatory:
Matt. 12:32 Anyone who speaks a word against the Son of Man will be forgiven, but anyone who speaks against the Holy Spirit will not be forgiven, either in this age or in the age to come.
Nothing is said here concerning sin being purged or paid for in purgatory. Finding purgatory in these words is eisogesis (reading into the text what is not already there), rather than exegesis (explaining the meaning of the text).
1 Cor. 3:11-13 For no one can lay any foundation other than the one already laid, which is Jesus Christ. If any man builds on this foundation using gold, silver, costly stones, wood, hay or straw, his work will be shown for what it is, because the Day will bring it to light. It will be revealed with fire, and the fire will test the quality of each man’s work.
The “fire” spoken of here has nothing to do with punishment, but only of separating out those “works” that have eternal value from those that do not.
When a person dies who has in this life truly surrendered his life to Jesus Christ as Savior and Lord, that person’s sins are already paid for on the cross and that person has been made holy and acceptable to God. There is no purgatory:
1 Pet. 3:18 For Christ died for sins once for all, the righteous for the unrighteous, to bring you to God.
Heb. 10:10 …we have been made holy through the sacrifice of the body of Jesus Christ once for all (see Rom. 6:10; Heb. 7:27; 9:12, 26).
1. The Catholic Encyclopedia (online edition)