Some Christians oppose the Harrowing of Hell doctrine.

Which I consider very problematic given the amount of Scriptural support the Harrowing of Hell has.

I've been an enthusiastic supporter of InspiringPhilsophy's videos on the Was Jesus a Copycat Savior playlist in-spite of my many doctrinal disagreements with him.  But the recently added video about Inanna includes him flat out saying there is no Biblical support for Jesus descending into the underworld.  I shall address how Christians should respond to this being compared to ancient Pagan myths at the bottom of this post.

Their only argument against it is Jesus telling the Thief on The Cross next to him that "I tell you this day you will be with me in Paradise".

1. If you believe the Parable of Lazarus and The Rich Man is an accurate literal depiction of how the After Life works (or did before The Cross) and not just an illustration based on the Pharisees own false views, it clearly has a Paradise in/next to Hades, Abraham's Bosom.

2.  My main argument on this.  An analysis of the actual Greek text can support putting a comma after "I tell you this day" meaning "this day" is not necessarily the day it will happen.  Jesus' Crucifixion wasn't normal ( a fact skeptics point out) most Crucifixion victims took days to actually die.  And the evidence of Jesus dying sooner then expected is in the Gospels text itself, He died before the Romans even got to the leg breaking part.  So chances are the thief didn't even die the same day Jesus did, especially given how in the Hebrew reckoning there was only like 3 hours left when Jesus died.

3. InspiringPhilosophy is an Old Earth Creationist who will say "A day is like a thousand years" when it suits him.  After all Adam didn't literally die within 24 hours of eating the fruit did he?  Actually this and option 2 go well together.

Now to the clear Biblical Support.  If you haven't read it yet, you should read my break down of what "Hell" is Biblically.  Before the Cross Sheol/Hades is where all the dead went, including the righteous like Jacob and David.

Isaiah 24:21-22 foretells it.  Likewise with Zechariah 9:11.  Psalm 16:10 and 83:13 where David says "For thou wilt not leave my soul in hell; neither wilt thou suffer thine Holy One to see corruption.".  Psalm 139:8 might be relevant as well.

In Matthew 12:39-41 and Luke 11:29-32 Jesus says "as Jonah was in The Belly of the Whale so shall the Sun of Man be in the Hear(Core) of The Earth".  In Jonah 2:2 Jonah felt like he was in Sheol/Hell when he was in the Belly of the Whale leading some to speculate he technically died, but that's besides my point here.  Numbers 16:30-33 and Deuteronomy 32:22 confirm that the Core of The Earth is where Sheol is.

In Acts 2:27-31 Peter quotes the above mentioned Psalms in reference to the Resurrection of Jesus.  Peter also discuses this in his Epistle (traditionally numbered as his first) to Jewish Churches in Asia Minor.  In Chapter 3 verses 19-20, and later in Chapter 4 verse 6 specifically saying Jesus proclaimed the Evangelion (Gospel) to the dead.

Paul in Romans 10:7 says Christ was in the Deep (Abyss).  Paul also discuses Christ's Descent to the "lowest parts" in Philippians 2:9-10 and Ephesians 4:7-10.

So Paul alludes to it three times, Peter said it on more then one occasion, two Old Testament Prophets foretold it, two Davidic Palms foretold it and Jesus said it in a statement recorded in two Gospels.  Frankly it's affirmed more repeatedly and unambiguously then The Virgin Birth and yet the later is considered more heretical to neglect today.

It's also supported by understanding Easter as the fulfillment of Passover.  Jesus died on the 14th of Nisan as the Passover Lambs were being Slaughtered.  After that the Lambs were roasted, and then after being eaten any leftovers were required to be burned up before sunrise on the morning of the 15th of Nisan.  So if there is indeed a fiery part of Hades/Sheol, Jesus traveled through it during those hours.  And then during the daylight hours of the 15th He delivered the saints in Sheol exactly when Israel was delivered out of Egypt.  On the 16th of Nisan which was a weekly Sabbath he rested, and then on the 17th, the day Mordecai was honored and Haman hanged, Jesus Rose from The Dead at Sunrise.  Matthew 27:51-53 records that others arose from their graves sometime after Jesus did.  Maybe that was later on the 17th, or maybe it was the 21st the last day of Unleavened Bread.

Seeing Egypt as Sheol typologically here is backed up by how Joseph is a type of Christ in Genesis. He was presumed dead to his family and then spent time as both a slave and prisoner in Egypt.  Then much later his body was taken out of Egypt at the Exodus.

The Early Church Fathers did affirm the doctrine, including Tertulian who IP likes to cite as the best Pre-Nicene precedent for a Homusion understanding of The Trinity.  And the Eastern Orthodox Church still considers it important to this day.  But it's come to be neglected in the West, possibly partially because of how it lends credence to Universal Salvation.

When some Richard Carrier type starts comparing this to Pagan myths about heroes or gods traveling to the Underworld, our response should be that Christ was Totally Victorious (1 Corinthians 15:55 "Grave" in the KJV is Hades).  Orpheus and Izanagi failed to save their Brides from Hades/Yomi, but Jesus got everyone out of Sheol/Hades he intended to (he may have completely emptied it and those in Hades in Revelation 20 have been added since, either way it will one day be fully emptied).  Inanna/Ishtar had to leave her Husband Dumuzid/Tammuz behind in her place, Jesus did not add anyone to Sheol to replace who he took out.

Basically, the Pagan versions are Bad News reinforcing the inevitability and inescapablness of Death.  The Gospel is The Good News, that as in Adam all Die so in Christ all shall be Made Alive, 1 Corinthians 15:22 (Cross reference with Romans 5).