Life is dependent on the air around us, and the quality of life is dependent on the quality of air. In an atmosphere of Torah and mitzvot there is healthy life. The first general step in healing is to purify the atmosphere, and is effected through the letters of Torah. When speaking words of Torah while in the store or walking in the street or riding the subway, one purifies the air.
Rabbi Yosef Yitzchak of Lubavitch
