I am looking for a sutta in which something is said--roughly: that unless one has suppressed the hindrances, one cannot see the welfare of self or other. Or that without jhāna one cannot see one's own welfare or anothers.
It says that ...
he cannot know or see, as it really is, what is to his own profit, nor can he know and see what is to the profit of others, or of both himself and others
... when overwhelmed and possessed by hindrances including ...
... but conversely ...
when a man dwells with his heart not possessed, not overwhelmed by sense-desires... ill-will... sloth-and-torpor... worry-and-flurry... doubt-and-wavering... [like the five bowls of water not as previously described, but 'clear, limpid, pellucid, set in the open']... then he knows and sees, as it really is, what is to his own profit, to the profit of others, to the profit of both himself and others. Then even sacred words he has not long studied are clear to him, not to mention those he has studied.
This sutta says that about "hindrances" and "profit of self and other", but I don't think it mentions jhāna.
Just to add to ChrisW's point on the SN 46.55 sutta. The jhanas are implied in that sutta for thru the jhanas, their 5 Jhana Factors are the key antidotes to the abandonement of the Five Hindrances:
- One-pointedness/ekaggata counter greed
- Joy/pity counter anger
- Applied thought/vitakka counter sloth/torpor
- Happiness/sukha counter restlessness
- Sustained thought/vicara counter doubt
With hindrances you do not properly look at one's welfare or others.
If there is water in a pot mixed with red, yellow, blue or orange color, a man with a normal faculty of sight, looking into it, could not properly recognize and see the image of his own face. In the same way, when one's mind is possessed by sensual desire, overpowered by sensual desire, one cannot properly see the escape from sensual desire which has arisen; then one does not properly understand and see one's own welfare, nor that of another, nor that of both; and also texts memorized a long time ago do not come into one's mind, not to speak of those not memorized.
— SN 46:55
Having hindrances one does not realise one's welfare or that of others but overcoming this then you do realise one's welfare and that of the others.
There are five impediments and hindrances, overgrowths of the mind that stultify insight. What five?
Sensual desire is an impediment and hindrance, an overgrowth of the mind that stultifies insight. Ill-will... Sloth and torpor... Restlessness and remorse... Sceptical doubt are impediments and hindrances, overgrowths of the mind that stultify insight.
Without having overcome these five, it is impossible for a monk whose insight thus lacks strength and power, to know his own true good, the good of others, and the good of both; nor will he be capable of realizing that superhuman state of distinctive achievement, the knowledge and vision enabling the attainment of sanctity.
But if a monk has overcome these five impediments and hindrances, these overgrowths of the mind that stultify insight, then it is possible that, with his strong insight, he can know his own true good, the good of others, and the good of both; and he will be capable of realizing that superhuman state of distinctive achievement, the knowledge and vision enabling the attainment of sanctity.
— AN 5:51
Jhana as means to overcome hindrances.
Applied thought, of the factors of absorptions (jhananga);
Energy, of the spiritual faculties (indriya);
Investigation of reality, energy and rapture, of the factors of enlightenment (bojjhanga).
When the mind is sluggish, it is not the proper time for cultivating the following factors of enlightenment: tranquillity, concentration and equanimity, because a sluggish mind can hardly be aroused by them.
When the mind is sluggish, it is the proper time for cultivating the following factors of enlightenment: investigation of reality, energy and rapture, because a sluggish mind can easily be aroused by them.
— SN 46:53
Sourced from: The Five Mental Hindrances and Their Conquest Selected Texts from the Pali Canon and the Commentaries compiled and translated by Nyanaponika Thera