Identification of a Quotation in the Ratnagotravibhāgavṛtti
I have been able to trace a hitherto unidentified quotation in the Ratnagotravibhāga(vrtti) (RGV(V)) to the Tathāgatagarbhasūtra (TGS). The sentence in question occurs in the RGV(V) in the context of the explanation of the three svabhāvas of the dhātu, viz., dharmakāya, tathatā and gotra, the three key terms of verses 1.27-28, which constitute the central section of the RGVV. The quotation is part of the commentary on the third aspect, i.e., gotra, and is placed after the last of the three interpretations of the compound tathāgatagarbha. In this context the dhātu of living beings, i.e., their buddha essence, has
just been declared to mean "cause" (hetu).