"There is, Ananda, one thing which, when developed and cultivated, fulfills four things; and four things which, when developed and cultivated, fulfill seven things; and seven things which, when developed and cultivated, fulfill two things." "But, venerable sir, what is the one thing which, when developed and cultivated, fulfills four things; and the four things which, when developed and cultivated, fulfill seven things; and the seven things which, when developed and cultivated, fulfill two things?" "Concentration by mindfulness of breathing, Ananda, is the one thing which, when developed and cultivated, fulfills the four establishments of mindfulness. The four establishments of mindfulness, when developed and cultivated, fulfill the seven factors of enlightenment. The seven factors of enlightenment, when developed and cultivated, fulfill true knowledge and liberation."
In The Buddha’s Words by Bhikkhu Boddi