This question has been crossing my mind for weeks; and I just saw this same question asked in a Denominational Specific Forum. The answers that I saw there still left me with the same question.
Here are the verses that prompted the question:
(CLV) Mt 12:40
For even as Jonah was in the bowel of the sea monster three days and three nights, thus will the Son of Mankind be in the heart of the earth three days and three nights.
(CLV) Lk 23:43
And Jesus said to him, "Verily, to you am I saying today, with Me shall you be in paradise."
Now here is a rhetorical question: Is the heart of the earth paradise?
So what did Yahshua mean by these two statements, which on the surface, would seem to be conflicting?
The Apostles' Creed confesses "He descended into the place of the dead". The Latin here is
descendit ad inferos, often translated as "descended into hell", though the more literal meaning of inferos is "lower regions" or "netherworld", i.e. the place of the dead, equivalent to Greek Hades and Hebrew She'ol.
Jesus descent into "hell" is for the purpose of freeing captives and defeating the powers of sin, death, hell, and the devil. For we read in the Epistle to the Hebrews, "Since therefore the children share in flesh and blood, He himself likewise partook of the same things, that through death He might destroy the one who has the power of death, that is, the devil," (Hebrews 2:14).
Paradise, or Gan-Eden was the part of She'ol where the righteous dead were waiting, this is "Abraham's Bosom" in Jesus' parable of the Rich Man and Lazarus. Second Temple period literature also "locates" Paradise in the so-called "third heaven", in the ancient Jewish concept of the seven heavens. St. Paul references this Second Temple idea when he speaks of a man he knew who experienced a vision or an experience of the third heaven seeing Paradise etc.
So yes, when Jesus says, "Today you will be with Me in Paradise" Jesus is telling the thief that he will be counted among the righteous; not that the thief will "go to heaven" since Paradise here isn't "heaven", but the place of the righteous dead, Gan-Eden, the righteous dead in She'ol.
All of this should sufficiently tell us that this isn't talking about some literal physical place either underground or somewhere in outer space. We aren't talking about "location" in the most literal way here.
Christ's descent into Hades is the doom of Hades, it is the defeat and victory over and against it. The Church calls this the Harrowing of Hell, and the Church has sung hymns and preached many sermons about it to remind us of Christ's glorious victory by His resurrection.
"
Christ is risen from the dead,
Trampling down Death by death,
And to those in the tombs,
Bestowing life." - The Paschal Troparion
"
Let no one grieve at his poverty,
for the universal kingdom has been revealed.
Let no one mourn that he has fallen again and again;
for forgiveness has risen from the grave.
Let no one fear death, for the death of our Savior has set us free.
He has destroyed it by enduring it.
He destroyed Hades when he descended into it.
He put it into an uproar even as it tasted of His flesh.
Isaiah foretold this when he said,
You, O Hell, have been troubled by encountering Him below.
Hell was in an uproar because it was done away with.
It was in an uproar, because it was mocked.
It was in an uproar, for it was destroyed.
It is in an uproar, for it is annihilated.
It is in an uproar because it is now made captive.
Hell took a body, and it discovered God.
It took earth, and encountered Heaven.
It took what it saw, and was overcome by what it did not see.
O death, where is your sting?
O Hades, where is your victory?
Christ is risen, and you, O death, are annihilated!
Christ is risen, and the evil ones are cast down!
Christ is risen, and the angels rejoice!
Christ is risen, and life is liberated!
Christ is risen, and the tomb is emptied of its dead;
for Christ, having risen from the dead,
is become the first-fruits of those who have fallen asleep.
To Him be glory and power forever and ever. Amen!"
- Paschal Homily of St. John Chrysostom
Amen, Christ is risen: Death is trampled down by death, Hell has been ransacked and the prison doors swung open. Christ the Lord has conquered, and by His conquering has set all creation free. Preach the Good News to every living creature: God has won, and the devil has lost. Whomever the Son sets free is free indeed.
-CryptoLutheran