The Rebbe told us that all his studies required great effort.

When he began to learn Mishnah¹⁶ as a young child, he did not understand it. He wept and wept until he was able to understand the Mishnah. Later, when he studied more advanced works, he again found himself unable to comprehend them. Again he cried bitterly until he was worthy of understanding. This was true even of such esoteric studies as the Zohar and the writings of the Ari, where understanding only came after long and bitter weeping.

footnotes: ¹⁶ The earlier part of the Talmud, redacted by Rabbi Yehudah HaNasi in 204 C.E. Mishnah is usually the first thing a child studied after completing the Torah.

He said that when he began to study any work, he did not understand it. It was very difficult for him and he could not grasp its straightforward meaning. This greatly distressed him. His studies required prodigious effort, but nevertheless, he studied a lot by constantly encouraging himself. He achieved it all through his prayer and weeping.