In Radha-kunda, sometime in 1934, my Guru Maharaja was living, and he was discussing Upanisad. He was discussing Upanisad regularly. And the babajis… There are many babajis in Radha-kunda. First of all, they came, that "Bhaktisiddhanta Sarasvati Thakura has come, such a learned scholar and the establisher of Gaudiya Matha." So out of curiosity they came. And when they saw that he was discussing Upanisad, gradually they stopped coming. So my Guru Maharaja recommended that "These people are not living in Radha-kunda. They are living in Naraka-kunda." I have heard it personally.

[Naraka means hell]

Srimad-Bhagavatam 6.3.20-23 — February 14, 1971, Gorakhpur