阿彌陀經通贊疏 2.128

2.128

贊曰：第二補處位高眾。一生補處者，補者補闕，處者處所，此等菩薩因圓十地、劫滿三祇，盡此一生便成正覺，故云一生補處也，餘經文易見故。只如彌勒現居天界當來果成，一生補大覺之尊、三會度無量之眾，即是此類。故《無量壽經》云：設我得佛，他方國土諸菩薩眾來生我國，究竟各到一生補處。以本願力故，生彼即入補處之位。

The commentary states: The second [part is] the assembly of high stage who are bound to one birth. Regarding 'bound to one birth' (ekajātipratibaddha): 'fill' (bu) means to fill a vacancy; 'place' (chu) means position. These bodhisattvas have perfected the cause of the ten grounds, fulfilled the kalpas of three asaṃkhyeyas, and at the end of this single life will immediately realize correct enlightenment; hence they are said to be 'bound to one birth' (a successor in one birth), as is easily seen in other sūtra texts. Just like Maitreya, who presently dwells in the heavenly realm and whose future fruition will be accomplished, in one life succeeding to the position of the Great Awakened Honoured One, delivering immeasurable assemblies in three convocations—he is of this kind. Hence the Amitāyus Sūtra says: If, when I attain buddhahood, the assemblies of bodhisattvas from other lands who come to be born in my land do not ultimately each reach the stage of being bound to one birth [I will not attain supreme awakening]. By the power of the original vow, upon being born there one enters the stage of being bound to one birth.'