As Nick Cave mentions in "A Song of Joy" (from the album Murder Ballads), the line "Red Right Hand" is from Milton's Paradise Lost.

The section of Paradise Lost follows:

Paradise Lost, Book II, Lines 163-176:

What can we suffer worse? Is this then worst,
Thus sitting, thus consulting, thus in arms?
What when we fled amain, pursued and strook
With Heaven's afflicting thunder, and besought
The deep to shelter us? This hell then seemed
A refuge from those wounds. Or when we lay
Chained on the burning lake? That sure was worse.
What if the breath that kindled those grim fires
Awaked should blow them into sevenfold rage
And plunge us in the flames? Or from above
Should intermitted vengeance arm again
His red right hand to plague us? What if all
Her stores were opened, and this firmament
Of hell should spout her cataracts of fire,

Nick Cave, in an interview about the song, had this to say:
From Spex, May 1994; Joerg-Uwe Albig: Nick Cave, Die Erkennbarkeit Gottes, pp. 26-29)

Spex: But here you're clearly talking about the devil.

Nick: I'm really not sure what about I'm talking there, to be really honest with you. I have to sing a few verses with the music that we have written together. I sang, how it was in my head ("Ich sang, wie es mir in den Kopf kam"). So this is a somewhat mysterious song for me. I suppose, Red Right Hand is a hand, plunged in blood, you know? It is the Evil. It is about someone, who pretends to be the saviour, but he isn't.

Spex: Consequently the Devil.

Nick: You can say that's the Devil. But it is only a song about... it is only that, what it is. ("Aber es ist einfach ein Lied ueber... es ist einfach das, was da ist")