大方廣佛華嚴經隨疏演義鈔 31.29

31.29

疏「然上云前後」下，第五別釋前後二字。「一生滅前後」者，此即竪說，如壯與老。謂此流水剎那生，前剎那滅、後剎那生。「二此彼前後」者，猶如二人同行狹徑，後人排前、前人引後，此即橫說。分分之水皆有前後，乃至毫滴亦有前毫後毫，故聚眾多皆成流注則無性矣。

Regarding the Commentary's statement starting with "However, the 'before and after' mentioned above": this is fifth, separately explaining the two characters 'before' and 'after'. Regarding "first, the before and after of arising and ceasing": this is a vertical explanation, like youth and old age. That is, this flowing water arises in an instant (kṣaṇa); the preceding instant ceases, and the subsequent instant arises. Regarding "second, the before and after of this and that": it is just like two people walking together on a narrow path, the person behind pushing the one in front, and the person in front pulling the one behind; this is a horizontal explanation. Every portion of water has before and after, down to a single drop also having a preceding part and a succeeding part; therefore, an accumulation of many all forms a stream, and hence is devoid of intrinsic nature.