Yoga is the restraint of the modifications of the mind.
Then there is abiding in the seer's own form.

~ The Yoga Sutras

The soul is its own witness, yea, the soul
Itself is its own refuge ; grieve thou not,
O man, thy soul, the great internal Witness.

~ Laws of Manu

All effort at controlling thoughts, appetites and desires
cannot but strengthen them along with the ego. What-
ever has to go must fall off by itself. All that you are
concerned with, all that you are, is the impersonal
functioning of understanding. So let that understanding
work through witnessing without judgment, knowing that
there is nothing else that you can do.

- Ramesh S. Balsekar

As you go about your life, don't give 100 percent of
your attention to the external world and to your mind.
Keep some within. Feel the inner body even when
engaged in everyday activities, especially when engaged
in relationships or when you are relating with nature.
Feel the stillness deep inside it. Keep the portal open.

~ Eckhart Tolle

Be aware of being conscious and seek the
source of consciousness. That is all. Very
little can be conveyed in words. It is the
doing as I tell you that will bring light, not
my telling you. The means do not matter much;
it is the desire, the urge, the earnestness that
counts.
- Nisargadatta Maharaj

My Master, Ramana Maharishi, said to me,
"God is not an object to be seen, He is the subject.
He cannot be seen, He is the Seer, find this Seer."
My Heart was opened.
"Find the Seer." This is the Teaching.
- Papaji

When the mind is quiet, we come to know ourselves as the pure witness. We withdraw from the experience and its experiencer and stand apart in pure awareness, which is between and beyond the two. The personality, based on self-identification, on imagining oneself to be something: ‘I am this, I am that’, continues, but only as a part of the objective world. Its identification with the witness snaps.

~ Nisargadatta Maharaj

To want nothing and do nothing - that
is true creation! To watch the universe
emerging and subsiding in one's heart
is a wonder.
- Nisargadatta Maharaj