Be patient, then, brothers and sisters, until the Lord’s coming. See how the farmer waits for the land to yield its valuable crop, patiently waiting for the autumn and spring rains. You too, be patient and stand firm, because the Lord’s coming is near. Don’t grumble against one another, brothers and sisters, or you will be judged. The Judge is standing at the door! (James 5:7-9, NIV).It's raining here on the Oregon Coast.
Much like Palestine, you see, we have two seasons: the wet, and the dry. The wet begins sometime in autumn and continues on through spring.
And everything here -- the trees, the fish, the osprey that lives on the baseball field near our church . . . it all needs the rain to start on time (i.e. "the early rain"), and to continue on until late in spring (i.e. "the latter rain").
The "early rain" and "latter rain" are not two distinct events, in other words. Instead, they are the bookends -- the beginning and end -- of one, long, continuous rainy season.
(And yes, the technical name for two opposites that stand for the whole is "merism." Think "near and far," for instance, or "night and day," or "alpha and omega.")
When Joel 2:23 predicted "the early rain and the latter rain," in other words, it did not say that it would begin to rain . . . then stop . . . then begin again. No, it promised that God's people would have all the rain they needed, from beginning to end.
And when Acts 2:16-21 says Joel's prophecy has been fulfilled, it is not saying that God's spirit will descend on the church . . . then stop . . . then descend again.
No, just as the promise of the remnant tells us that God will always have a people who love and follow Him, so too the promise of latter rain tells us that God will always love and lead His people.
In short, it is the promise of Matthew 28:20b -- "And surely I am with you always," said Jesus, "to the very end of the age."