Deuteronomy 11:14

The rain - in his due season, the first rain and the latter rain - By the first or former rain we are to understand that which fell in Judea about November, when they sowed their seed, and this served to moisten and prepare the ground for the vegetation of the seed. The latter rain fell about April, when the corn was well grown up, and served to fill the ears, and render them plump and perfect. Rain rarely fell in Judea at any other seasons than these. If the former rain were withheld, or not sent in due season, there could be no vegetation: if the latter rain were withheld, or not sent in its due season, there could be no full corn in the ear, and consequently no harvest. Of what consequence then was it that they should have their rain in due season! God, by promising this provided they were obedient, and threatening to withhold it should they be disobedient, shows that it is not a general providence that directs these things, but that the very rain of heaven falls by particular direction, and the showers are often regulated by an especial providence.