The 28th of Adar is the Yahrtzeit of Rav Mordechai Kastelanitz of Lecovitz, the father of the Slonim Chassidic dynasty. “It is vain for you to be early in rising, to be late in sitting up, eating the food of sadness; for so does He give to His beloved sleep (Psalms 127:2).”
Many pious people attempt to serve God buy arising before sunrise and remaining up late in order to study Torah. They eat the food of the spirit in sadness, and their brain is confused for lack of sleep. King David, however, teaches us that this is the wrong way to study. He advises us to give to God sufficient sleep that we may thereby gain a clear head for sacred studies. Then his sleep is as acceptable to God as his study (Ohr Yesharim, page 18).