What is the
Ability called Concentration?

Concentration is the
ability to focus all mental factors on 1 single object!
Concentration (samādhi) is a mental ability,
and a power, when stabilized...
Concentration is a
Link to
Awakening & a
Factor on the Noble 8-fold Way.
Concentration is
non-distraction, non-scatter, and non-diffusion of mind...
Concentration is collecting together, unifying, focusing,
and condensing!
Making
mental release the object the Noble Disciple gains Samādhi,
achieves one-pointedness, and enters fixed, unified mental
absorption..
The Definition of these 4 subtle Mental
Jhāna Absorptions:
Having
eliminated the
5 mental hindrances,
the mental defects that
obstruct
any
understanding, while quite secluded from all
sensual-desires,
and protected
from
any
detrimental mental state, one enters and dwells in the 1st jhāna; full
of joy
and
pleasure born of solitude, joined with directed thought and sustained thinking.
With the stilling of directed
thought and sustained thinking, one enters and
dwells
in the
2nd jhāna, calmed assurance and unification of mind with joy
and
pleasure
now
born of concentration, devoid of any thinking!
With the fading away of joy, in equanimity,
clearly
comprehending, one enters
upon
and remains in the 3rd jhāna, still
feeling pleasure in the body, about which
the Noble
Ones declare: In aware equanimity one abides in Happiness...
With the
leaving behind of both pleasure and pain, as with the prior cessation of
both joy and sorrow, one enters and dwells in the 4th jhāna mental
absorption,
which is
an entirely stilled mental state of awareness, purified by the equanimity
of neither-pain-nor-pleasure!

The 1st Entrance:
As long as a
Bhikkhu does not perceive the disappearance of the
5
hindrances
in
himself,
he feels as if in debt, in sickness, in bonds, in slavery, on a desert journey.
But when he
perceives the
disappearance of the five hindrances in himself, it is as if he
were freed
from the debt, from the sickness, the bonds, the slavery, and from the desert dangers...
And when he knows that these
5 mental hindrances
have left him, then gladness arises
in him, from gladness comes joy, from the joy in his mind, his body is tranquillised!
With a calm body he delights in happiness, and this happiness
concentrates his mind.
Thus secluded from
sense-desires, isolated from detrimental states,
he enters and
remains in the 1st jhāna, which
contains
directed reflection
and sustained evaluation,
born of seclusion, filled with pleasure and joy. With this
pleasure & joy born of seclusion,
he so permeates, drenches, fills and pervades his whole body that there is not even a
single spot in his body, that is not saturated by this pleasure,
and joy born of seclusion...
The Similes:
As, your
majesty, all rafters there are in a house with a ridged roof, they all lead to the
ridgepole, incline towards the ridgepole, lean on the ridgepole,
and this beam is termed
their peak summit, even and exactly just so, your Majesty, whatever advantageous
mental states there are, all of these are headed by concentration, incline towards
concentration, lean on concentration, is based on concentration ...
As, your majesty, a King might enter battle with an army of 4 parts, and the whole
army,
the elephants, horses, chariots and foot-soldiers would be headed by him, incline towards
him, lean on him, and tend towards him, would follow after just him, even exactly so is this
unique concentration the chief, the captain, the commander, and the conductor of the
orchestra of mental states..
Milindapanha
38
The Explanation:
It is
concentration that places and anchors the mind evenly on only 1 single object,
it settles and collects mind rightly together there.
Its characteristic is
absence of
all wandering, dispersal, and distraction. Its function is joining and binding together
of co-arisen mental states as water does for bath-powder. Its manifestation is
calming,
tranquillization, stilling, ceasing and peace.
Its proximate cause is especially happiness.
It should be seen as fixed steadiness of the mind, like the
fine stilled steadiness of a
candle-flame in complete absence of any perturbing
wind...
Visuddhimagga
XIV 139

Jhāna
is excessively and addictively pleasant ;-)
On
how to attain the Jhāna absorptions:
https://What-Buddha-Said.net/drops/Details_of_the_Jhana_Absorptions.htm
https://What-Buddha-Said.net/drops/Requisites_for_Jhana_Absorption.htm
https://What-Buddha-Said.net/drops/III/The_Concentration_Ability.htm
https://What-Buddha-Said.net/drops/What_is_Right_Concentration.htm
https://What-Buddha-Said.net/drops/III/Feeding_Concentration.htm
https://What-Buddha-Said.net/drops/III/Concentration_Samadhi.htm
https://What-Buddha-Said.net/library/DPPN/wtb/g_m/jhaana.htm
https://What-Buddha-Said.net/drops/IV/Jhana_Absorption.htm
https://What-Buddha-Said.net/drops/Samma-Samadhi.htm