瑜伽論記 5.174

5.174

又有六種最極清淨等者，則六恒住。又有六法乃至謂四大種，空界識界者，色所依謂大種，非色所依謂識界，行動所依謂空界，故唯說六以成有情，由此初言是諸色根及所依處隨其所應之所依止。

Regarding 'moreover, there are six kinds of utmost purification, etc.', these are the six constant abidings. Regarding 'moreover, there are six dharmas... up to... referring to the four great elements, the space element, and the consciousness element': the basis of form is the great elements; the basis of non-form is the consciousness element; the basis of movement is the space element; therefore, only six are stated to constitute sentient beings. Because of this, it is stated at the beginning: 'These are the bases upon which the physical faculties and their physical bases rely, as appropriate.'