A beautiful reflection on the same, from Crisis Magazine.
The second reading from the Office of Readings for Holy Saturday is taken from an ancient homily on Christ’s descent into hell. It begins: “Something strange is happening—there is a great silence on earth today, a great silence and stillness. The whole earth keeps silence because the King is asleep.” The King fell asleep when His soul was separated from His body on Good Friday afternoon. He remained asleep until His soul reanimated His body on Easter morning. But during the silence and stillness of the King’s sleep, He harrowed hell.
Our Lord’s descent into hell is well attested to by divine revelation. For example, Christ says, “… as Jonah was three days and three nights in the belly of a whale, so will the Son of man be three days and three nights in the belly of the earth” (Mt. 12:40). Further, in Acts of the Apostles, St. Peter says, “[David] foresaw and spoke of the resurrection of the Christ, that he was not abandoned to Hades, nor did his flesh see corruption” (2:31). Likewise in the Apostles’ Creed we profess, “He descended into hell.”
Besides making clear that the soul of Christ descended into hell, these texts clearly refer the descent into hell to the Person of Christ. And this is supremely fitting. For, since the personal union of the Word of God with both His body and soul remained even after death, whatever could be attributed to either of these principles of His human nature, while they were separated, was also attributable to God the Son. Thus, in the Apostles’ Creed we profess that He (i.e., God the Son) was buried insofar as His body was placed in the tomb. In like manner, we profess that God the Son descended into hell on account of His soul going to the underworld.
Connected with this, St. Thomas Aquinas points out that it is even true to say that “during the three days of His death, the whole Christ was in the tomb, in hell, and in heaven, on account of His Person, which was united to His body lying in the tomb, and to His soul harrowing hell, and which was subsisting in His divine nature reigning in heaven” (Compendium theologiae, ch. 229). Indeed, insofar as by His divine immensity the Son of God comprehends or contains all things, we must affirm that the whole Person of Christ is both in every place and in all places put together, yet He is not wholly contained by any one place nor by all places put together (Summa theologiae, III, q 52, a. 3, ad 3um).
Retrieved April 17, 2014 from http://www.crisismagazine.com/2014/the-harrowing-of-hell