起信論疏筆削記 1.32

1.32

隨派下，喻明也。水分流謂之派，路分徑謂之岐。今取岐派共為一喻，謂如一源之水隨何岐路分流成派。真心亦爾，隨何因緣作凡聖等，如下即明。

From "Following the branches..." onwards explains through a simile. When water diverges in its flow, it is called a "branch" (派); when a road forks into paths, it is called a "fork" (岐). Here, forks and branches are taken together as a single simile, meaning that just as water from a single source divides its flow into branches according to whatever fork in the road it meets, the true mind is likewise: in accordance with whatever causes and conditions, it becomes ordinary beings, sages, and so forth, as will be clarified below.