Concerning the Descent to Hades.

The soul when it was deified descended into Hades, in order that, just as the Sun of Righteousness rose for those upon the earth, so likewise He might bring light to those who sit under the earth in darkness and shadow of death: in order that just as He brought the message of peace to those upon the earth, and of release to the prisoners, and of sight to the blind, and became to those who believed the Author of everlasting salvation and to those who did not believe a reproach of their unbelief, so He might become the same to those in Hades: That every knee should bow to Him, of things in heaven, and things in earth and things under the earth. And thus after He had freed those who had been bound for ages, straightway He rose again from the dead, shewing us the way of resurrection.

SAINT JOHN OF DAMASCUS: AN EXACT EXPOSITION OF THE ORTHODOX FAITH, BOOK III,CHAPTER XXIX