首楞嚴義疏注經 7.84

7.84

第一劫者，發心修行之初時也。洎乎菩薩最後身時，故名後身。於其中間不落雜類，或生人中亦非貧賤，以持尊勝法故身尊勝也。

"The first aeon" refers to the initial time of generating the resolve and practicing. Up until the bodhisattva's time of the last rebirth, it is called the "final rebirth." During this intermediate period, one will not fall into mixed kinds of beings; even if born among humans, one will not be poor or lowly, because by upholding the supremely noble Dharma, one's body is supremely noble.