AN 4.94
Samadhi Sutta: Concentration (Tranquillity and Insight)
translated from the Pali by
Thanissaro Bhikkhu

"Monks, these four types of individuals are to be found existing in the world. Which four?

"There is the case of the individual who has attained internal tranquillity of awareness, but not insight into phenomena through heightened discernment. Then there is the case of the individual who has attained insight into phenomena through heightened discernment, but not internal tranquillity of awareness. Then there is the case of the individual who has attained neither internal tranquillity of awareness nor insight into phenomena through heightened discernment. And then there is the case of the individual who has attained both internal tranquillity of awareness & insight into phenomena through heightened discernment.

"The individual who has attained internal tranquillity of awareness, but not insight into phenomena through heightened discernment, should approach an individual who has attained insight into phenomena through heightened discernment and ask him: 'How should fabrications be regarded? How should they be investigated? How should they be seen with insight?' The other will answer in line with what he has seen & experienced: 'Fabrications should be regarded in this way. Fabrications should be investigated in this way. Fabrications should be seen in this way with insight.' Then eventually he [the first] will become one who has attained both internal tranquillity of awareness & insight into phenomena through heightened discernment.

"As for the individual who has attained insight into phenomena through heightened discernment, but not internal tranquillity of awareness, he should approach an individual who has attained internal tranquillity of awareness... and ask him, 'How should the mind be steadied? How should it be made to settle down? How should it be unified? How should it be concentrated?' The other will answer in line with what he has seen & experienced: 'The mind should be steadied in this way. The mind should be made to settle down in this way. The mind should be unified in this way. The mind should be concentrated in this way.' Then eventually he [the first] will become one who has attained both internal tranquillity of awareness & insight into phenomena through heightened discernment.

"As for the individual who has attained neither internal tranquillity of awareness nor insight into phenomena through heightened discernment, he should approach an individual who has attained both internal tranquillity of awareness & insight into phenomena through heightened discernment... and ask him, 'How should the mind be steadied? How should it be made to settle down? How should it be unified? How should it be concentrated? How should fabrications be regarded? How should they be investigated? How should they be seen with insight?' The other will answer in line with what he has seen & experienced: 'The mind should be steadied in this way. The mind should be made to settle down in this way. The mind should be unified in this way. The mind should be concentrated in this way. Fabrications should be regarded in this way. Fabrications should be investigated in this way. Fabrications should be seen in this way with insight.' Then eventually he [the first] will become one who has attained both internal tranquillity of awareness & insight into phenomena through heightened discernment.

"As for the individual who has attained both internal tranquillity of awareness & insight into phenomena through heightened discernment, his duty is to make an effort in establishing ('tuning') those very same skillful qualities to a higher degree for the ending of the (mental) fermentations.

"These are four types of individuals to be found existing in the world."