Note the similarities!
First from Enoch:
I saw the spirits of the children of men who were dead, and their voice went forth to heaven and made suit. Then I asked Raphael the angel who was with me, and I said unto him: "This spirit- whose is it, whose voice goeth forth and maketh suit?" And he answered me saying: "This is the spirit which went forth from Abel, whom his brother Cain slew, and he makes his suit against him [Cain] till his seed is destroyed from the face of the earth, and his seed is annihilated from amongst the seed of men."
Enoch 22:5-7
Next from the Revelation to John:
And when the Lamb opened the fifth seal, I saw under the altar the souls of those who had been slain for the word of God and for the testimony they had upheld. And they cried out in a loud voice, “How long, O Lord, holy and true, until You avenge our blood and judge those who dwell upon the earth?”
Then each of them was given a white robe and told to rest a little while longer, until the full number of their fellow servants, their brothers, were killed, just as they had been killed.
Rev 6:9-11
Also consider this statement recorded by Moses. The setting? Cain has just killed his brother Abel.
And the LORD said to Cain, “Where is your brother Abel?”
“I do not know!” he answered. “Am I my brother’s keeper?”
Gen 4:9
The Lord knew what had happened. His response:
“What have you done?” replied the LORD. “The voice of your brother’s blood cries out to Me from the ground."
Gen 4:10
I don't think the statement “The voice of your brother’s blood cries out to Me from the ground" is just a figure of speech.
The standard Christian assumption is that when you die, your soul goes straight to heaven (or hell).
This comes more from later theology than from what the Hebrew Bible or even the earliest NT writings spell out.
In the OT, all the dead go to Sheol (righteous and wicked alike).
Nowhere in Torah or Prophets is there a clear idea of “heaven” as the final destiny of the righteous dead.
In some places, Sheol is described as a diminished existence—conscious in some sense (cf. Isaiah 14:9–11), but cut off from active life and praise (Psalm 6:5; 115:17).
The Book of Enoch is a prime example. Abel’s spirit isn’t in heaven yet; it’s in a waiting-place, making petition.
That's also what we see in the Revelation to John:
I saw under the altar the souls of those who had been slain for the word of God and for the testimony they had upheld...
“How long, O Lord, holy and true, until You avenge our blood and judge those who dwell upon the earth?”
Rev 6:9-10
But that's not the end of the story!
For context, see: Sheol
