Matakabhattajātaka
“If folk but knew.”—This story was told by the Master while at Jetavana about Feasts for the Dead. For at this time the folk were putting to death goats, sheep, and other animals, and offering them up as what is called a Feast for the Dead, for the sake of their departed kinsmen. Finding them thus engaged, the Brethren asked the Master, saying, “Just now, sir, the folk are taking the lives of many living creatures and offering them up as what is called a Feast for the Dead. Can it be, sir, that there is any good in this?”
Translated by Bhikkhu Sujato · Pāli: Mahāsaṅgīti Tipiṭaka · Public domain (CC0) via SuttaCentral
1.1PTS 1.168“Evañce sattā jāneyyuṁ,If beings only knew11.2dukkhāyaṁ jātisambhavo;how this suffering is created by birth,1.3Na pāṇo pāṇinaṁ haññe,no creature would kill another,1.4pāṇaghātī hi socatī”ti.for the slayer of creatures grieves.
2.1Matakabhattajātakaṁ aṭṭhamaṁ.
A goat is being prepared for a sacrifice as an offering for the departed, but it startles with its alternate laughing and weeping. It turns out, it laughs because it knows its bad kamma is about to be expiated, and it weeps because it knows the sacrificer will suffer as he has. Goat sacrifice was known since Vedic times (Rig Veda 1.162, Śatapatha Brāhmaṇa 6.2.1.2).
