Objection 1. It would seem that Christ did not make any stay in hell. For Christ went down into hell to deliver men from thence. But He accomplished this deliverance at once by His descent, for, according to Sirach 11:23: "It is easy in the eyes of God on a sudden to make the poor man rich." Consequently He does not seem to have tarried in hell.
Objection 2. Further, Augustine says in a sermon on the Passion (clx) that "of a sudden at our Lord and Saviour's bidding all 'the bars of iron were burst'" (Cf. Isaiah 45:2). Hence on behalf of the angels accompanying Christ it is written (Psalm 23:7-9): "Lift up your gates, O ye princes." Now Christ descended thither in order to break the bolts of hell. Therefore He did not make any stay in hell.
Objection 3. Further, it is related (Luke 23:43) that our Lord while hanging on the cross said to the thief: "This day thou shalt be with Me in paradise": from which it is evident that Christ was in paradise on that very day. But He was not there with His body. for that was in the grave. Therefore He was there with the soul which had gone down into hell: and consequently it appears that He made no stay in hell.
On the contrary, Peter says (Acts 2:24): "Whom God hath raised up, having loosed the sorrows of hell, as it was impossible that He should be held by it." Therefore it seems that He remained in hell until the hour of the Resurrection.
I answer that, As Christ, in order to take our penalties upon Himself, willed His body to be laid in the tomb, so likewise He willed His soul to descend into hell. But the body lay in the tomb for a day and two nights, so as to demonstrate the truth of His death. Consequently, it is to be believed that His soul was in hell, in order that it might be brought back out of hell simultaneously with His body from the tomb.
Reply to Objection 1. When Christ descended into hell He delivered the saints who were there, not by leading them out at once from the confines of hell, but by enlightening them with the light of glory in hell itself. Nevertheless it was fitting that His soul should abide in hell as long as His body remained in the tomb.
Reply to Objection 2. By the expression "bars of hell" are understood the obstacles which kept the holy Fathers from quitting hell, through the guilt of our first parent's sin; and these bars Christ burst asunder by the power of His Passion on descending into hell: nevertheless He chose to remain in hell for some time, for the reason stated above.
Reply to Objection 3. Our Lord's expression is not to be understood of the earthly corporeal paradise, but of a spiritual one, in which all are said to be who enjoy the Divine glory. Accordingly, the thief descended locally into hell with Christ, because it was said to him: "This day thou shalt be with Me in paradise"; still as to reward he was in paradise, because he enjoyed Christ's Godhead just as the other saints did.
Source: Summa Theologica (New Advent)