Be patient, therefore, brothers, until the coming of Adonai. See how the farmer waits for the precious fruit of the earth, being patient about it, until it receives the early and the late rains. You also, be patient. Establish your hearts, for the coming of Adonai is at hand.
Egypt received its water from below, from the regular flooding of the Nile leaving fertilizing sediments behind. Anyone could grow a crop in Egypt; it was almost guarantied (Deuteronomy 11:10). The Children of Israel were now going to a place where their increase and their success will require for them to be on good terms with 'Heaven' (Deuteronomy 11:11-14).
I live in Western Oregon, a place that receives its fair share (and more) of rain from September to May, sometimes even June. I drink water from my own well tapping an underground spring of melted snows. Water is never an issue here but in the Middle East downpours and water rights are at the heart of economics, politics, and even religion. It used to even be the sources of wars. Grain, wine, and oil speak of abundance and form the imagery of Messiah and the Messianic age. In the Promised Land this abundance will be dependent on obedience, and the 'early' and 'late' rain from 'above'. As well as being a natural reality, it is a reminder of where our attention should be!
These two seasonal downpours have particular names in Hebrew: 'yoreh', and 'malkosh'; they could respectively be translated as 'Spring', and 'Autumn' rain. They refer to the rains that come in the Spring around the season of Passover, and the Fall after the Feast of tabernacles.
Messiah manifested Himself to the world at the time of the 'Yoreh', the Spring festivals rains around the time of Passover. It is significant that the word 'Yoreh' originates from the verbal root 'to teach, to instruct', and therefore is connected to the word 'Torah': 'Instruction'.
The prophets often poetically play on those words alluding between rain, teaching, and Torah which come down from Heaven, as well as the Messiah (Deuteronomy 32:2;Joel 2:23; Hoseah 6:3; 10:12).
After the Spring rains, comes the long hot summer of Messiah's absence, a time of harvesting wheat and barley, ending with the fruit harvest in the Fall and the Feast of Tabernacles also called 'Ingathering', because this is when the harvest is gathered into barns. As reliable servants, may we be faithful with the harvest of souls He has entrusted with at His first manifestation (Matthew 28:18-20), that when He returns in the Fall, He may receive His own with interest.