Comparing Torah to Rain

Parshas Ha'azinu employs extensive allegory to describe the future relationship between Hashem and the Jewish people, both the good and the bad. Translating the imagery into practical insights is no small task. Allow me to share one sweet thought I read regarding the pasuk (32:2): "Ya'arof ke'matar likchi, tizal katal imrati - Let my instruction flow like rainfall; let my sayings drip like dew" - essentially comparing the Torah to rain and dew.

What's the meaning of this particular comparison?