Here is how Fa-tsang begins his commentary:
The True Mind that is serene and vast is separate from the words and
forms found in the fish nets and hare snares (of deluded conceptualization).
Abstrusely boundless, invisible and inaudible, it is neither the object of that
which knows nor the subject of that which is known. It is neither produced nor
destroyed and is not something affected by the four momentary states.*
Neither coming nor going, none of the three time periods can change it. But, taking
non-abiding as its nature, it flows and branches, rising and falling in accord with (the
arising of) delusion and enlightenment. So, in dependence on causes and
conditions it does arise and is destroyed. Nevertheless, though multitudes of
phenomena repeatedly arise, rousing and popping about, (such activity) has never
yet moved the Mind’s Origin. Still and quiet, empty yet formed, it does not stand
in opposition to karmic results. So, utilizing an unchanging nature it nevertheless
dependently arises so that the pure and the impure are constantly differentiated.
Yet, in not abandoning conditions as Thusness, the sage and the common man
become one. It is just like waves which because they are not different than the
water’s movement, are just the water differentiated into waves. Furthermore,
because the water itself is not different than the stream of flowing waves, it is just
the waves manifest on the water. Because of this, movement and quiescence
interpenetrate, the ultimate and the conventional interfuse, and samsara and
nirvana uniformly pervade one another.
* Four momentary states (四 相): The “four avasthå,” or characteristic
marks of phenomena. Conditioned phenomena are subject to production, abiding,
change, and destruction.
May all seek, find & follow the Path of Buddhas.
Nam mô A di đà Phật 
Nam mô Quan Thế Âm Bồ tát