dorchadas | (Reply)

From:

Jesus may have been referring to the physical place (and that's definitely where the name originally came from), but it was already a spiritual concept in the time of R. Hillel and R. Shammai (1st century BCE), at least according to the Mishna (compiled 2nd century CE):

"The House of Shammai says, 'There are three groups, one for eternal life, one for shame and everlasting contempt (Dan 12:2)—these are those who are completely evil.
An intermediate group go down to Gehinnom and scream and come up again and are healed, as it is said: “I will bring the third part through fire and will refine them as silver is refined and will test them as gold is tested, and they shall call on my name and I will be their God” (Zech 13:9). And concerning them did Hannah say, “The Lord kills and brings to life, brings down to Sheol and brings up” (1 Sam 2:6).

And the House of Hillel says: “Great in mercy” (Exod 34:6)—He inclines the decision toward mercy, and concerning them David said: “I am happy that the Lord has heard the sound of my prayer” (Ps 116:1), and concerning them is said the entire passage."
-Tosephta Sanhedrin 13.3