Once, the children of the 3rd Chabad Rebbe, Rabbi Menachem Mendel of Lubavitch, sat with their father in discussion of Maimonides’ Guide to the Perplexed.[1]
The Rebbe remarked:
“My grandfather—the Alter Rebbe—said about the Rambam that he had a strong stomach—he was able to consume the snakes and scorpions of philosophy and not be harmed.”
The Rebbe continued:
“My grandfather remarked that he himself had a strong stomach, as do I. However, you children do not and for you it is forbidden to learn.”
He pointed to one of his children, saying: “and you for sure should not.”
[1] Ramach Otiot, #94.
