成唯識論述記 7.190

7.190

述曰：四大、空、識能成有情，不言心所成有情故。五十六說：此密意說，唯色、動、心所三法最勝所依，故唯說六。處處經說，通大、小乘有。

The Commentary states: The four great elements, space, and consciousness are capable of constituting a sentient being, but it does not say that mental factors constitute a sentient being. The fifty-sixth fascicle says that this is spoken with intentional meaning, because matter, motion, and mental factors are the supreme bases of these three dharmas, which is why only six are spoken of. It is spoken in sūtras everywhere, common to both Mahāyāna and Hīnayāna.