瑜伽師地論略纂 8.172

8.172

論云「世尊依彼作如是說，乃至於外沙門、婆羅門教空無所有」等者，此中意，明四種聲聞，世尊依真教有彼作如是說。有其外沙門等教是邪教，乃至壞道亦無所有，要受真戒，方生壞故。彼既邪戒，設壞，非壞道。

The treatise says: "The World-Honoured One, relying upon them, spoke in this way, up to: in the external teachings of śramaṇas and brāhmaṇas, there is nothing whatsoever," and so forth. The meaning here is to clarify the four kinds of śrāvakas, about whom the World-Honoured One spoke in this way relying on the true teaching. The teachings of external śramaṇas and so forth are heterodox teachings, and even a corruptor of the path does not exist [among them], for one must receive the true moral discipline before corruption can arise. Since their discipline is heterodox discipline, even if broken, it is not corrupting the path.