The Blessed
Buddha once
explained:
Whenever
while withdrawn in
body and withdrawn in
mind one reflects on the
Buddha-Dhamma,
then the
Awareness Link to Awakening
arises and develops.
Thus
acutely
aware
one
examines
that
awareness
itself..
Whenever
examining
a mental state, then the
Investigation Link to Awakening
arises and develops. While thus
being curious and
enthusiastically
investigating,
keen
energy is now aroused!
Whenever energy is aroused in one who is enthusiastic,
then the Energy Link
to
Awakening
arises
and
develops.
When energetic
and enthusiastic
one succeeds:
Therefore
Joy is born
from
that
advance.
Whenever
achieving in
eager joy, then the
Joy Link to Awakening arises
and
develops. One thus joyous becomes
mentally satisfied, and
therefore calmed
both in
body and in mind!
Whenever calmed in body
and mind,
then the Tranquillity Link to Awakening
arises
and develops. One thus satisfied,
calmed, serene, settled
and tranquil
in both body
and mind becomes
exquisitely
Happy!
Whenever calmed
and comfortable in the body,
and
tranquil & happy in
the mind,
then the
Concentration Link to Awakening arises
and develops. When
mentally
concentrated one reviews all
states rationally
and
reasonably, as if from
above..
Whenever
one well
balanced
reviews
all
phenomena
rationally and
realistically,
then the
Equanimity Link to Awakening arises
and develops. In
Equanimity one
knows and sees
things just so, right as they
really are now, and later
become.
It is in this very way
that The Seven
Links to Awakening
develop sequentially,
one after the
other; successively one
leading to, and producing the next...

On these 7 Links to Awakening
(Sambojjhanga):
https://What-Buddha-Said.net/drops/III/The_Sun.htm
https://What-Buddha-Said.net/drops/III/The_Peak.htm
https://What-Buddha-Said.net/drops/III/The_Clothes.htm
https://What-Buddha-Said.net/drops/III/Rare_Emergence.htm
https://What-Buddha-Said.net/drops/III/Vast_Penetration.htm
https://What-Buddha-Said.net/drops/III/The_Seven_Fruits.htm
https://What-Buddha-Said.net/drops/III/Unsurpassable_Seven.htm

Source (edited
extract):
The Grouped
Sayings of the
Buddha. Samyutta Nikāya.
Book [V:
67-69]
section 46: The
Links.3:
Morality....