CC Adi-lila 17.308 - Mahabharata
Sri Caitanya-caritamrta
CC Adi-lila
CC Adi 17.308, Translation and Purport:
"Anything transcendental to material nature is called inconceivable, whereas arguments are all mundane. Since mundane arguments cannot touch transcendental subject matters, one should not try to understand transcendental subjects through mundane arguments."
This verse from the Mahābhārata (Bhīṣma-parva 5.22) is also quoted in the Bhakti-rasāmṛta-sindhu (2.5.93), by Śrīla Rūpa Gosvāmī.