In Torah portion Haazinu we read “My lessons [i.e. the Torah] will drip like rain; my word will flow like dew” (Deut. 32:2). Water is often used as a metaphor for Torah; both promote growth and are vital for human life. But what is the significance of rain and dew specifically?
Rain and dew represent two types of spiritual experiences. One comes from above, like rain. This describes moments of Divine inspiration, when we feel like God is speaking to us. Dew, on the other hand, emerges from the ground. This type of inspiration comes from within ourselves, when we do the inner work necessary to improve our own character.
This verse tells us that a life of Torah must include both of these elements. We look above for Divine wisdom, and internalize that wisdom by looking within.