Answer:
Here is one of the scriptures, there are others but this immediately comes to mind.
Ephesians 4:8-10 Wherefore he saith, When he ascended up on high, he led captivity captive, and gave gifts unto men. (Now that he ascended, what is it but that he also descended first into the lower parts of the earth? He that descended is the same also that ascended up far above all heavens, that he might fill all things.)
You can see from this verse that from the cross He then descended into the lower part of the earth (not just the tomb but down into the spirit world) so that he might release the captives, the Old Testament saints.
He did not go into the feiry hell as we know it, he went to a section of the “underworld” called paradise where the saints of old were and they were released and seen by some until the time of Jesus resurrection some 40 days later where they are now in Heaven with him. Paradise is now empty because of Jesus work on the cross, today a believer is instantly in Heaven when they die.
The part of hell full of torment and fire is still there and grows despite Jesus wish that “none should perish”.
Very good question. There are whole books written on this subject and the parts of the underworld according to scripture.
Pastor Brad