釋禪波羅蜜次第法門 6.106

6.106

第一、明證相者，行者既一心念空不捨，則其心泯然，任運自住空緣。此亦似如前說未到地之相。於後豁然，與空相應，其心明淨，不苦不樂，益更增長，於深定中唯見虛空，無諸色相。雖緣無邊虛空，心無分散。既無色縛，心識澄靜，無礙自在，如鳥在籠中，籠破得出，飛騰自在。證虛空定亦復如是。

First, explaining the marks of realization: once the practitioner single-mindedly attends to space without letting go, their mind becomes quiet and still, naturally dwelling of itself on the condition of space. This also resembles the mark of anāgamya explained earlier. Thereafter, one suddenly accords with space: the mind is bright and pure, neither painful nor pleasant, increasing even further; within deep absorption, one sees only empty space and no marks of form. Although conditioning upon boundless space, the mind is not scattered. Having no bondage of form, the mental consciousness is clear and calm, unobstructed and free—just like a bird in a cage that gains release when the cage breaks, flying freely. The realization of the space absorption is also like this.