Said Rabbi Yosef Yitzchak of Lubavitch:
Two life-sustaining influences radiate from the sun: light and warmth. Light may penetrate certain substances, but not others: a glass partition allows light to pass, but not a partition of rawhide. The warmth exuded by the sun is more powerful, and can be felt through the coarser and more opaque barriers.
The same is true of the luminary of Torah. Torah sheds light, illuminating and enlightening our minds with the divine wisdom. It also bathes the Jewish heart with the warmth of G-d’s love for His people.
The light of Torah will pass through certain barriers, reaching into many an alienated mind with its wisdom and truth. But if the barrier has grown too coarse—if a soul has sunk so deeply into material life that a corporeal hide seals the frontiers of its consciousness—the power of reason and the light of truth will not penetrate the folly and darkness of this life. But the warmth of Torah will. A kind and caring word will achieve what the most profound arguments and the most glaring truths will not. And once a little warmth seeps through, the hideous walls of mundanity will give way, and the light will come pouring in as well.
Adapted from the teachings of the Rebbe by Yanki Tauber