俱舍論頌疏論本 17.96

17.96

釋曰：三障者，標也。無間業者，出業障體，謂五無間業名為業障：一害母、二殺父、三害阿羅漢、四破和合僧、五出佛身血。

Explanation: "The three obstructions" states the topic. "Immediate karmas" identifies the entity of the karmic obstruction; that is, the five immediate karmas are called karmic obstructions: (1) killing one's mother, (2) killing one's father, (3) killing an arhat, (4) causing a schism in the Saṅgha, and (5) shedding the blood of a Buddha.