God is the Father of precipitation, Job says (Job 38:25-30). Rain is filial, the Father’s nourishing gift to the world.
The same imagery appears elsewhere. The righteous king is “like rain upon the mown grass” (Psalm 72:6), and the king’s “favor is like a cloud with the spring rain” (Proverbs 16:15). Yahweh “rained down manna upon [Israel] to eat . . . He rained meat upon [Israel] like dust” (Psalm 78:24, 27), and we know that the rain of manna pointed ahead to the true Bread that would fall from heaven (John 6).
And if we talk about filial rain, we must also talk about the wind that drives the rain.
“Hey, ho, the wind and the rain. The rain it raineth everyday”: Shakespeare spoke more theologically than he knew.