Vajirūpamasutta
“Tayome, bhikkhave, puggalā santo saṁvijjamānā lokasmiṁ. Katame tayo? Arukūpamacitto puggalo, vijjūpamacitto puggalo, vajirūpamacitto puggalo. Katamo ca, bhikkhave, arukūpamacitto puggalo? Idha, bhikkhave, ekacco puggalo kodhano hoti upāyāsabahulo appampi vutto samāno abhisajjati kuppati byāpajjati patitthīyati kopañca dosañca appaccayañca pātukaroti. Seyyathāpi, bhikkhave, duṭṭhāruko kaṭṭhena vā kaṭhalāya vā ghaṭṭito bhiyyoso mattāya āsavaṁ deti; evamevaṁ kho, bhikkhave, idhekacco puggalo kodhano hoti upāyāsabahulo appampi vutto samāno abhisajjati kuppati byāpajjati patitthīyati kopañca dosañca appaccayañca pātukaroti. Ayaṁ vuccati, bhikkhave, arukūpamacitto puggalo.
Like Diamond
“These three individuals are found in the world. What three? An individual with a mind like an open sore, an individual with a mind like lightning, and an individual with a mind like diamond. And who has a mind like an open sore? It’s an individual who is irritable and bad-tempered. Even when lightly criticized they lose their temper, becoming annoyed, hostile, and hard-hearted, and they display annoyance, hate, and bitterness. They’re like a festering sore, which, when you hit it with a stick or a stone, discharges even more. In the same way, an individual is irritable and bad-tempered. Even when lightly criticized they lose their temper, becoming annoyed, hostile, and hard-hearted, and they display annoyance, hate, and bitterness. This is called an individual with a mind like an open sore.