All dharmas are 'One Dharma', 'One Taste', and realising this
nonduality is necessary especially for all Mahayana and bodhisattva
practitioners:
Q: Some of these Nondual traditions, particularly the Tantra,
get pretty wild.
KW: Yes, some of them get pretty wild. They are not afraid of
samsara, they ride it constantly. They don't abandon the defiled
states, they enter them with enthusiasm, and play with them, and
exaggerate them, and they couldn't care less whether they are
higher or lower, because there is only God.
In other words, all experiences have the same One Taste. Not a
single experience is closer to or further from One Taste, You
cannot engineer a way to get closer to God, for there is only God -
the radical secret of the Nondual schools.
At the same time, all of this occurs within some very strong
ethical frameworks, and you are not simply allowed to play Dharma
Bums and call that being Nondual. In most of the traditions, in
fact, you have to master the first three stages of transpersonal
development (psychic, subtle, and causal) before you will be
allowed to talk about the fourth or Nondual state. "Crazy wisdom"
occurs in a very strict ethical atmosphere.
But the important point is that in the Nondual traditions, you take
a vow, a very sacred vow, which is the foundation of all of your
training, and the vows is that you will not disappear into cessation
- you will not hide out in nirvana, you will not evaporate in
nirodh, you will not abandon the world by tucking yourself into
nirvikalpa.
Rather, you promise to ride the surf of samsara until all beings
caught in that surf can see that it is just a manifestation of
Emptiness. Your vow is to pass through cessation and into
Nonduality as quickly as possible so you can help all beings
recognize the Unborn in the very midst of their born
existence.
So these Nondual traditions do not necessarily abandon emotions, or
thoughts, or desires, or inclinations. The task its simply to see
the Emptiness of all Form, not to actually get rid of all Form. And
so Forms continue to arise, and you learn to surf. The
Enlightenment is indeed primordial, but this Enlightenment
continues forever, and it forever changes its Form because new
Forms always arise, and you are one with those.
So the call of the Nondual traditions is: Abide as Emptiness,
embrace all Form. The liberation is in the Emptiness, never in the
Form, but Emptiness embraces all forms as a mirror all its objects.
So the Forms continue to arise, and, as the sound of one hand
clapping, you are all those Forms. You are the display. You and the
universe are One Taste. Your Original Face is the purest Emptiness,
and therefore every time you look in the mirror, you see only the
entire Kosmos.
According to the Idealists - and the Nondual sages everywhere -
the extraordinary and altogether paradoxical secret is that the
Final release is always
already accomplished. The "last step" is to step off the
cycle of time altogether, and find the Timeless there from the start, every-present from the
very beginning and at every
point along the way, with no deviations whatsoever.
"The Good," says Hegel, "the absolutely Good, is eternally
accomplishing itself in the world; and the result is that it need
not wait upon us, but is already
in full actuality accomplished."
I have one last quote for you, from Findlay, one of Hegel's great
interpreters: "It is by the capacity to understand this that the
true Hegelian is marked off from his often diligent and scholarly,
but still profoundly misguided misinterpreter, who still yearns
after the showy spectacular climax, the Absolute coming down...
accompanied by a flock of doves, when a simple return to utter
ordinariness is in place [cf. Zen's "ordinary mind"].
Finite existence in the here and now, with every limitation, is, Hegel
teaches, when rightly regarded and accepted, identical with the
infinite existence which is everywhere and always. To live in Main
Street is, if one lives in the right spirit, to inhabit the Holy
City."
As Plotinus knew and Nagarjuna taught: always and always, the other
world is this world rightly seen. Every Form is Emptiness
just as it is. The radical
secret of the supreme identity is that there is only God. There is
only the Kosmos of One Taste, always already fully present, always
already perfectly accomplished, always already the sound of one
hand clapping. And the very belief that we could deviate from this is the
arrogance of the egoic delusion, the haunting mask of divine egoism
gloating over the smoking ruins of its own contracting
tendencies. We can preserve nature. but Nature preserves
us.
- A Brief History of Everything, Ken Wilber
But most importantly still, is that we must be awakened to that
reality 
p.s The 'God' here refers to Dharma Nature/Buddha Nature.
