Here's Tg. Pseudo-Jonathan on Geneses 3:24 (Etheridge [PJE in BW]):Also the Targum on Ruth 2:12 is referenced:And He drave out the man from thence where He had made to dwell the glory of His Shekina at the first between the two Kerubaia. Before He had created the world, He created the law; He prepared the garden of Eden for the righteous, that they might eat and delight themselves with the fruit of the tree; because they would have practised in their lives the doctrine of the law in this world, and have maintained the commandments: (but) he prepared Gehinnam for the wicked, which is like the sharp, consuming sword of two edges; in the midst of it He hath prepared flakes of fire and burning coals for the judgment of the wicked who rebelled in their life against the doctrine of the law. To serve the law is better than (to eat of) the fruit of the tree of life, (the law) which the Word of the Lord prepared, that man in keeping it might continue, and walk in the paths of the way of life in the world to come.He also references Tg. Isaiah (B. Chilton's trans.):12- "May the Lord reward you well in this world for your good work, and may you receive full recompense from the Lord, the God of Israel, in the world to come, because you have come to be a proselyte and to seek shelter under the shadow of His Glorious Presence. Through that merit you will be saved from the punishment of Gehinom, so that your portion will be with Sarah and Rebecca and Rachel and Leah." (Levey's translation)Given the targumic texts above, I don't know if I'd go as far as saying that the teaching was that Gehenna/hell-fire was intended to be fueled by Gentiles as much as by "the wicked".27.1 In that time the LORD with his great and strong and hard sword will punish the king who exalts himself like Pharaoh the first king, and the king who prides himself like Sennacherib the second king, and he will slay the king who is strong as the dragon that is in the sea. 27.2 In that time, "The congregation ofIsrael which is like a choice vineyard in a good land, sing of it! 27.3 I, the LORD, keep for them the covenant of their fathers, and I will not destroy them, except that in the moment that they incite to anger before me, I make them drink the cup of their retribution. But though their sins already demand that retribution be taken from them, night and day my Memra protects them. 27.4 Behold, there are many prodigies before me! If the house of Israel set their face to do the law, would I not send my anger and my wrath among the Gentiles who are stirred up against them and destroy them as the fire destroys briers and thorn together? 27.5 Or if they laid hold of the words of my law, peace would be made with them,from then on peace would be made with them."
33.14 Sinners in Zion are shattered; fear has seized them. To the wicked whose ways are thieving they say, "Who can dwell for us in Zion, where the splendour of the Shekhinah is like a devouring fire? Who can sojourn for us in Jerusalem, where the wicked are about to be judged and handed over to Gehenna, everlasting burning?"
I'd like to see a specific citation that either equates "Gentile" with "Wicked" or something to the effect. At length Balfour quotes some guy named Whitby. The same quotation from Whitby is cited in Gwynne's commentary on Galatians (p. 92) where he states that it's from Whitby's comments on Romans 2:13. Gwynne's lengthy quote of Whitby's comments references the "first sentence in the Capitula Patrum" (Pirke Aboth), but I don't see any evidence of anti-Gentile sentiment in the various English translations of Pirke Aboth that I could consult from home.
I'll see if I can track anything down at work.