'Dew' in the Bible

My doctrine shall drop as rain, My speech flow down as dew, As small rain upon the tender herb, And as showers on the grass.

And of Joseph he said, Blessed of Jehovah be his land! By the precious things of the heavens, By the dew, and by the deep that lieth beneath,

And Israel shall dwell in safety alone, The fountain of Jacob, in a land of corn and new wine; Also his heavens shall drop down dew.