The mind of loving-kindness
If anyone should give you a blow with his hand, with a clod, with a stick, or with a knife, [124] you should abandon any desires and any thoughts based on the household life. And herein you should train thus: ‘My mind will be unaffected, and I shall utter no evil words; I shall abide compassionate for his welfare, with a mind of loving-kindness, without inner hate.’ That is how you should train, Phagguna.
“Monks, there are these five courses of speech that others may use when they address you: their speech may be timely or untimely, true or untrue, gentle or harsh, connected with good or with harm, spoken with a mind of loving-kindness or in a mood of hate. When others address you, their speech may be timely or untimely; when others address you, their speech may be true or untrue; when others address you, their speech may be gentle or harsh; when others address you, their speech may be connected with good or with harm; when others address you, their speech may be spoken with a mind of loving-kindness or in a mood of hate. Herein, monks, you should train thus: ‘Our minds will remain unaffected, and we shall utter no bitter words; we shall abide compassionate for their welfare, with a mind of loving-kindness, never in a mood of hate. We shall abide pervading that person with a mind imbued with loving-kindness, and starting with that person,21 we shall abide pervading the all-encompassing world with a mind imbued with loving-kindness, abundant, exalted, immeasurable, without hostility, and without ill will.’ That is how you should train, monks…. 20.
Monks, even if bandits were to sever you savagely limb by limb with a two-handled saw, he who gave rise to a mind of hate toward them would not be carrying out my teaching. Herein, monks, you should train thus: ‘Our minds will remain unaffected, and we shall utter no bitter words; we shall abide compassionate for their welfare, with a mind of loving-kindness, never in a mood of hate. We shall abide pervading them with a mind imbued with loving-kindness; and starting with them, we shall abide pervading the all-encompassing world with a mind imbued with loving-kindness, abundant, exalted, immeasurable, without hostility, and without ill will.’ That is how you should train, monks. 21.
“Monks, if you keep this advice on the simile of the saw constantly in mind, do you see any course of speech, trivial or gross, that you could not endure?”—“No, venerable sir.”—“Therefore, monks, you should keep this advice on the simile of the saw constantly in mind. That will lead to your welfare and happiness for a long time.” (from MN 21: Kakacūpama Sutta; I 126–27, 129