唯識二十論述記 1.198

1.198

述曰：此鋒刃增中，第三鐵刺林。謂此林上，有利鐵刺，長十六指，罪人被逼，若上樹時，其刺即低，向下而刺。若下樹時，其刺即昂，向上而刺，有鐵𭪿烏，揬啄有情眼精、心肝，諍共而食，皆是罪者業生大種差別轉變。然此林刺實是非情，非此所諍，但諍獄卒及鐵𭪿烏、羝羊山等。因舉苦具，顯其惡相，非鐵林刺亦此所論。上來總是薩婆多救義。

The Commentary says: Among the adjunct hells of blade-edges, this is the third, the Iron Thorn Forest. In this forest there are sharp iron thorns sixteen finger-widths long; when sinners are driven to climb the trees, the thorns bend down to prick downward. When they descend the trees, the thorns point up to prick upward; and there are iron-beaked crows that peck out and feed upon the sentient beings' pupils, hearts, and livers, fighting with one another to eat them. All these are distinct transformations of the great elements arisen from the sinners' karma. However, these forest thorns are truly insentient; they are not what is disputed here. What is disputed are only the hell-wardens, the iron-beaked crows, the Ram Mountains, and the like. Because the instruments of suffering were mentioned to show their evil characteristics, the iron forest thorns are not themselves the primary topic of debate here. Everything up to this point is the Sarvāstivāda's rescue argument.