大般涅槃經義記 6.176

6.176

解佛以為天人師中，初六復次廣解天義，次四復次廣釋人義。人天多義，且舉斯耳。下解如來為天人師，初先標舉，「何以」下釋，「是故」下結。

In explaining the Buddha being a teacher of gods and humans, the first six turns extensively explain the meaning of 'gods', and the next four turns extensively explain the meaning of 'humans'. Gods and humans have many meanings; these are merely cited. Below, in explaining the Tathāgata as a teacher of gods and humans, first it marks it out, from 'why' onward it explains, and from 'for this reason' onward it concludes.