妙法蓮華經玄義 4.20

4.20

As for the eight spheres of mastery: the position of the first two spheres of mastery is in the first dhyāna; the position of the third and fourth spheres of mastery is in the second dhyāna; the position of the latter four spheres of mastery is in the fourth dhyāna. Because the third dhyāna has much bliss and the mind is dull, none are established there. In the preceding liberations, one does not attain sovereignty over whether the objects are few or many; therefore, in the spheres of mastery, one contemplates more deeply and minutely few, many, fine, and ugly, causing all to become mastered knowledge and mastered vision—just like a swift horse that can break an enemy battle line and can also be restrained by its rider (and so forth).