維摩經略疏 4.28

4.28

「所以者何至樹下」，二、述不堪之由，由於林中宴坐樹下。宴坐者，有云縮止如龜藏六。縮止六識六塵，魔不能惱，故言縮止。今明宴之言安，安住根本淨禪乃至滅定，息外勞累，似涅槃法安置心中身，證想受滅，故言宴坐。

From "Why is this?" to "under a tree" is second: recounting the reason for being unequal, which was due to quiet sitting under a tree in the forest. As for quiet sitting, some say it is contracting and stopping like a tortoise concealing its six [limbs]. Contracting and stopping the six consciousnesses and six sense objects so that Māra cannot disturb them is therefore called contracting and stopping. Now it is explained that the word yàn (quiet) means peaceful: peacefully abiding in the fundamental pure dhyānas up to the cessation concentration, resting from external toil and weariness, placing in the body of the mind what resembles the dharma of nirvāṇa, and realizing the cessation of perception and feeling; hence it is called quiet sitting.