坐禪三昧經 2.9

2.9

Gradually contemplating the sphere of space, he shatters perceptions of internal and external forms, eradicates perceptions of resistance, and does not think upon perceptions of various forms; contemplating the sphere of boundless space, he constantly contemplates the faults of form; he thinks upon the superior, subtle virtues of the concentration of the sphere of space. Practicing mindfulness of this dharma, he attains the sphere of space.