Psalm 68:18 You have ascended on high, You have led captivity captive;
You have received gifts among men
This is prophetic about what took place during Christ death, before His ascension. He emptied the grave of all those, who by faith, believed in the coming Lord, but could not go to heaven yet. This place is called paradise, or Abrahams bossom. It was seperate from hell, where unbelievers go. When Christ' sacrifice was completed, He emptied this out. Its not purgatory. This also speaks of the resurrection, in that Messiah would Ascend, rise!