There is the case where a monk is content with any old robe cloth at all. He speaks in praise of being content with any old robe cloth at all. He does not, for the sake of robe cloth, do anything unseemly or inappropriate. Not getting cloth, he is not agitated. Getting cloth, he uses it not tied to it, uninfatuated, guiltless, seeing the drawbacks (of attachment to it), and discerning the escape from them. He does not, on account of his contentment with any old robe cloth at all, exalt himself or disparage others. In this he is skillful, energetic, alert, and mindful. This, monks, is said to be a monk standing firm in the ancient, original traditions of the Noble Ones.
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Not getting almsfood, he is not agitated.
Not getting lodging, he is not agitated.
AN 4.28
And the well-known simile of the Saw:
"Monks, even if bandits were to carve you up savagely, limb by limb, with a two-handled saw, he among you who let his heart get angered even at that would not be doing my bidding. Even then you should train yourselves: 'Our minds will be unaffected and we will say no evil words. We will remain sympathetic, with a mind of good will, and with no inner hate. We will keep pervading these people with an awareness imbued with good will and, beginning with them, we will keep pervading the all-encompassing world with an awareness imbued with good will — abundant, expansive, immeasurable, free from hostility, free from ill will.' That's how you should train yourselves.
MN21