Yoga Sūtra Chapter One verse 13

तत्र स्थितौ यत्नोऽभ्यासः ॥१३॥

tatra sthitau yatnaḥ abhyāsaḥ ||13||

Practice is the effort to remain there.

tatra - in that place, there; thither, to that place; in that, therein, in that case, on that occasion, under those circumstances, then, thereforesthiti - staying or remaining or being in any state or condition; maintenance of life;yatna - effort, exertion, energy, zeal, trouble, pains, care, endeavour after; performance, work; activity of will, volition, aspiring afterabhyāsa - practice; the effort of the mind to remain in its unmodified condition of purity ; repeated or permanent exercise, discipline, use, habit, custom;

Commentaries and Reflections

Commentary by T Krishnamacharya:

Abhyāsa is the practice of reflecting on the difference
between the nature of Jīva and the nature of Prakṛti,
which brings momentary tranquillity to the mind and
eventually leads to complete and sustained mental tranquillity.”

Commentary by TKV Desikachar:

“How do you know the use of the right means is good?”

“The spirit of Abhyāsa is to always verify the best means to go from one step to another.”

“The starting point for Abhyāsa is not the mind,
it is other than the mind.
The moment the mind takes over you are in difficulty.”

“Any Abhyāsa is only for the mind,
you cannot go beyond that point.”

Commentary by Paul Harvey:

Meditation is about the quality of the effort,
rather than the fruit of the time.”

“In Jñāna Dhyānam the most
difficult exercise for the mind is
the one of not exercising the mind.”

“In Sūtra 1.13 Patañjali succinctly
defines the aim of Abhyāsa as
the effort to remain there.
What is the ‘effort‘ mentioned here?
Where is the ‘there‘ mentioned here?”

“Finally, the consideration of movement
or stasis sits within a relationship to the
deeper purpose of Āsana within our journey
through the body and the breath, to the mind
and beyond, through considerations such as:
In relation to the psychological ideal of remaining there.
According to the definition in  Chapter Three verse 2 of
the Yoga Sūtra, a continuity of psychic activity is the ideal.
This is seen as the ability to stay, as if in the same moment, as
one moment melds into the next moment and the next moment.
In other words, the ability to internally maintain a continuity of
experience as if maintaining an apparent stillness of movement.
Access to such subtle states requires a containment of movement
that ultimately extends from the body to the breath to the mind.”

Inspirational Quote

“To listen is an effort, and just to hear is no merit. A duck hears also.” Igor Stravinsky