Why aren't you a Christian?

[Angrboda]

The Jews in the OT had no concept of afterlife or hell but believed EVERYBODY went to Sheol or 'the pit' (also, the 'unknown'). They eventually learned about from their neighbors (the Greeks).

Minor technical point, Sheol in the Old Testament was not the only place later identified with hell. Both Sheol and Gehenna (a valley in the neighborhood of Jerusalem) are identified with the references in the New Testament. Gehenna appears to have originally referred to a literal place, but Jewish lore gave it additional interpretations. Hades or Hell, as referenced in the New Testament (10 times) appears to refer to Sheol. Another word which is translated as Hell in the New Testament is actually Gehenna (Gehinnom in the Hebrew; 11 times).



For by fire and by his sword will the Lord plead with all flesh: and the slain of the Lord shall be many.

They that sanctify themselves, and purify themselves in the gardens behind one tree in the midst, eating swine's flesh,
and the abomination, and the mouse, shall be consumed together, saith the Lord.

For I know their works and their thoughts: it shall come, that I will gather all nations and tongues;
and they shall come, and see my glory.

And I will set a sign among them, and I will send those that escape of them unto the nations, to Tarshish, Pul, and Lud,
that draw the bow, to Tubal, and Javan, to the isles afar off, that have not heard my fame, neither have seen my glory;
and they shall declare my glory among the Gentiles.

And they shall bring all your brethren for an offering unto the Lord out of all nations upon horses, and in chariots, and in litters,
and upon mules, and upon swift beasts, to my holy mountain Jerusalem, saith the Lord, as the children of Israel bring an offering
in a clean vessel into the house of the Lord.

And I will also take of them for priests and for Levites, saith the Lord.

For as the new heavens and the new earth, which I will make, shall remain before me, saith the Lord, so shall your seed and your name remain.

And it shall come to pass, that from one new moon to another, and from one sabbath to another, shall all flesh come to worship before me, saith the Lord.

And they shall go forth, and look upon the carcases of the men that have transgressed against me:
for their worm shall not die, neither shall their fire be quenched; and they shall be an abhorrence unto all flesh.

— Isaiah 66:16-24 (this is referring to Gehenna - where the worm does not die)


(Best I can tell from my limited research, this is a reference to a victory over the Assyrians.)