“...and the graves were opened; and many bodies of the saints who had fallen asleep were raised; and coming out of the graves after His resurrection, they went into the holy city and appeared to many.”
“For this reason the gospel was preached also to those who are dead, that they might be judged according to men in the flesh, but live according to God in the spirit.” ~ 1 Peter 4-6
These are interesting statements because we see in the prophesies of Isaiah the “anointed” coming to proclaim the good news and to release the captives, being those in actual prisons or those that are “stuck” in the Other-world, such as those mentioned in 1 Peter 3:19.
One of books whose use by Christians was documented in the third century was the Gospel of Nicodemus. It is currently listed in the Apocrypha. It includes an intensive and detailed narration of the journey of Christ through the underworld. Its account tells how Jesus was able to release from Hell the “Just”, the non-baptized people that died before the time Christ himself had walked the earth. It affirms that the non-Just souls had closed the underworld with seven seals. We can see some of the same doctrinal idea in Chapter VIII of the Apocrypha titled The Liberation of the Patriarchs:
"And the Lord stretching forth his hand, said: Come unto me, all ye my saints which bear mine image and my likeness. Ye that by the tree and the devil and death were condemned, behold now the devil and death condemned by the tree. And forthwith all the saints were gathered in one under the hand of the Lord."