CC Adi 17.164
- aśvamedhaṁ gavālambhaṁ
- sannyāsaṁ pala-paitṛkam
- devareṇa sutotpattiṁ
- kalau pañca vivarjayet
aśva-medham—a sacrifice offering a horse; gava-ālambham—a sacrifice of cows; sannyāsam—the renounced order of life; pala-paitṛkam—an offering of oblations of flesh to the forefathers; devareṇa—by a husband’s brother; suta-utpattim—begetting children; kalau—in the Age of Kali; pañca—five; vivarjayet—one must give up.
“‘In this Age of Kali, five acts are forbidden: the offering of a horse in sacrifice, the offering of a cow in sacrifice, the acceptance of the order of sannyāsa, the offering of oblations of flesh to the forefathers, and a man’s begetting children in his brother’s wife.’
This is a quotation from the Brahma-vaivarta Purāṇa (Kṛṣṇa-janma-khaṇḍa 185.180).