Dutiyasiṅgālasutta

Sāvatthiyaṁ viharati. “Assuttha no tumhe, bhikkhave, rattiyā paccūsasamayaṁ jarasiṅgālassa vassamānassā”ti? “Evaṁ, bhante”. “Siyā kho, bhikkhave, tasmiṁ jarasiṅgāle yā kāci kataññutā kataveditā, na tveva idhekacce sakyaputtiyapaṭiññe siyā yā kāci kataññutā kataveditā. Tasmātiha, bhikkhave, evaṁ sikkhitabbaṁ: ‘kataññuno bhavissāma katavedino; na ca no amhesu appakampi kataṁ nassissatī’ti. Evañhi vo, bhikkhave, sikkhitabban”ti. Dvādasamaṁ. Opammavaggo paṭhamo.

At Sāvatthī. “Mendicants, did you hear an old jackal howling at the crack of dawn?” “Yes, sir.” “There might be some gratitude and thankfulness in that old jackal, but there is none in a certain person here who claims to follow the Sakyan. So you should train like this: ‘We will be grateful and thankful. We won’t forget even a small thing done for us.’ That’s how you should train.”

Kūṭaṁ nakhasikhaṁ kulaṁ, okkhā satti dhanuggaho; Āṇi kaliṅgaro nāgo, biḷāro dve siṅgālakāti. Opammasaṁyuttaṁ samattaṁ.

The Linked Discourses with similes are complete.