The fact that Jesus rose from the dead implies that He dwelt with the dead, as their Savior; to deliver the souls of the just that came before Him. His proclamation of the Gospel to those who were dead fulfills the messianic mission to offer all peoples of all times and all places a share in the power of redemption, and thus salvation. For through the death of the Lord, death has been destroyed (cf. 1 Corinthians 15:55) and those in the depths of death may hear the Word of God and rise to life, moving from captivity to freedom.
Through the Word becoming flesh, the Son of God assumed the entirety of human nature, including the penalty of the sons of Adam, that is, death. In His death, His body and soul separated, His body rested in the tomb and His soul resided in the house of the dead, while His divinity was with His body and soul in spite of their separation. He did not, however, merely die. He died on the sacrificial altar of the cross, and it is through the cross that victory has been won.
This victory is carried with Him as He enters into the house of the dead. His mere presence in solidarity with them is a proclamation of victory to the souls imprisoned by death. This solidarity with those in solitude puts them into communion, which is their liberation. For the Son, having been given all authority and power by the Father to judge the living and the dead, did not come to judge but to save.
St. Athanasius, a Father of the Church, said: “The Son of God became the Son of Man so that the sons of men could become the sons of God.” In an analogous fashion, the Author of Life was put to death so that the dead may enter into eternal life. This mystery conveys the great compassion of the Lord, for out of compassion, the Lord visited the deepest misery of humanity, in order to escort humanity to the fullness of joy. He who has descended into the depths of darkness has made His ascent into the heights of heavenly light with those who dwelt in darkness. He has cast out from them the spirit of slavery and fulfilled their hope, filling them with the Spirit of Sonship, by which they see the face of the Father whom they praise.
Thus the dead enter into Christ's death because Christ entered into their death. This is similar to how we die and rise with Christ through baptism (cf. Romans 6). The souls of the just rose with Christ when He rose from the dead. By dying, He made death a road to life, and brought life to the dead. This solidarity with the dead is a form of preaching, in which the Word is spoken to the soul in the depths of loneliness. Those that hear, are brought out of the solitude of death and into the communion of life, while those who reject the Word, suffer deeper and continued isolation. Thus, to the just who receive this joy are given the vision of God, fulfilling the Lord’s word to St. Dismas, the good thief on the cross next to Him, “Today you will be with me in paradise (Luke 23:43).”
Here it seems necessary to clarify: Christ’s descent into Hell is the entrance of His soul into death, not damnation. The difference is shown in the parable of Lazarus and the rich man (see Luke 16:19-31). The realm of the dead is divided into those who are in “bosom of Abraham” and “Hades” or Hell as we normally understand it. Prior to the resurrection all children of Adam suffered the punishment of sin - death (cf. Romans 5:12 and Romans 6:23). Put simply, those who lived righteous lives awaiting the coming of the Messiah, while those who lived wicked lives reside in Hades. While Christ’s soul enters into solidarity with all of the dead, the righteous who dwell in the bosom of Abraham are those who respond to His preaching of presence through solidarity. This concept can also be seen in St. Thomas Aquinas in reference to the effect of the descent being throughout all of the realm of the dead, even to the depths of damnation, while only the fruit of salvation from the tree of the Cross are given to the just.
The descent into hell proclaims the power and authority of Christ. So great is His power that death is powerless in comparison, and so great is His authority that the chaos of the realm of the dead is put into order by His presence. Thus the descent serves to confirm that at the name of Jesus, every knee will bend, in heaven, on earth, and under the earth (cf. Philippians 2:10). The Catechism of the