Said Rabbi Yosef Yitzchak of Lubavitch:
When I was a child attending cheder, our teacher, Rabbi Nissan Skoblo, would conclude each day of study with a story.
In our little village, where matches were a luxury, the custom was to bury a smoldering coal from the day’s fire in ashes before retiring to bed in the evening. In the morning, one would blow on this coal and bring forth a spark with which to start the new day’s fire.
Such was the effect of our teacher’s story at the end of the school day. Every evening, he would bury a silent ember in our hearts, from which he would draw a renewed desire for study on the following morning.