"How are you faring?" the pious man asked his friend the scribe "Fine," he said "so long as my arm is sound" That very evening he shattered his arm and could no longer write. Divine retribution for having placed his trust in his arm."
pg 467
Nefesh Hachaim
Pausing to recharge one's Yirat Shamayim in the midst of his Torah learning will recharge and preserve his studies.
Gate Four Chapter 7 pg 144
Pirkei Avos
Midrash Tanchuma: All souls were present at Mount Sinai, Each soul has a connection to a particular aspect of the Torah, this is why one person is attached to one particular mitzvah while another person will "connect" to a different one.
Alshich on Avos Mishnah 1 pg 5
