Nadī Sutta SN 45.160
“Suppose, bhikkhus, that when the river Ganges slants, slopes, and inclines towards the east, a great crowd of people would come along bringing a shovel and a basket, thinking: ‘We will make this river Ganges slant, slope, and incline towards the west.’ What do you think, bhikkhus, would that great crowd of people be able to make the river Ganges slant, slope, and incline towards the west?”
“No, venerable sir.
For what reason?
Because the river Ganges slants, slopes, and inclines towards the east, and it is not easy to make it slant, slope, and incline towards the west. That great crowd of people would only reap fatigue and vexation.”
“So too, bhikkhus, when a bhikkhu is developing and cultivating the Noble Eightfold Path, kings or royal ministers, friends or colleagues, relatives or kinsmen, might invite him to accept wealth, saying: ‘Come, good man, why let these saffron robes weigh you down? Why roam around with a shaven head and a begging bowl? Come, having returned to the lower life, enjoy wealth and do meritorious deeds.’ Indeed, bhikkhus, when that bhikkhu is developing and cultivating the Noble Eightfold Path, it is impossible that he will give up the training and return to the lower life.
For what reason?
Because for a long time his mind has slanted, sloped, and inclined towards seclusion. Thus it is impossible that he will return to the lower life.
“And how, bhikkhus, does a bhikkhu develop and cultivate the Noble Eightfold Path? Here, bhikkhus, a bhikkhu develops right view … right concentration, which is based upon seclusion, dispassion, and cessation, maturing in release. It is in this way, bhikkhus, that a bhikkhu develops and cultivates the Noble Eightfold Path.”
Source: Nadī Sutta SN 45.160 SN v 53 Translated by Bhikkhu Bodhi /https://suttacentral.net/sn42.6