瑜伽論記 6.292

6.292

就第二別約三四重指當中，初言此中所說住光明想乃至謂由正念及由正知者，舉初夜中所起思二與中夜無染污心睡眠為緣，所謂正念正知。次言復由二緣乃至及由思惟起想者，復由初夜二心為緣令於後夜以時悎寤起，不釋初夜過時謂由住光明想及思惟起想。此復云何已下，重釋初夜四門，二興中夜無染睡眠為緣，二與後夜起不過時為緣所以。

Regarding the second, specifically pointing back in terms of the third and fourth: first, saying 'what is explained here as abiding in the perception of light... up to: that is, by right mindfulness and by clear comprehension' cites the two thoughts arisen in the early night as conditions for sleep with an undefiled mind in the middle watch, namely right mindfulness and clear comprehension. Next, saying 'furthermore, due to two conditions... up to: and by the perception of arising through reflection' means that two thoughts of the early night serve as conditions causing one to wake up in good time during the late night, not oversleeping the early night, namely by abiding in the perception of light and the perception of arising through reflection. From 'How is this again?' downward, it reiterates why among the four aspects of the early night, two serve as conditions for undefiled sleep in the middle watch, and two serve as conditions for waking in the late night without exceeding the proper time.