"I will give the rain of your land in its season, the first rain and the last rain, that you may gather in your corn, and your wine, and your oil" (Deuteronomy 11:14).
Here we shall address the meaning of the word "yoreh" (first rain) based upon explanations given by the sages of the Talmud in tractate Taanit (6a).
"Our rabbis have taught: [The first rain is termed] 'yoreh' because it warns people to plaster their roofs and to gather in their fruits and to attend to all their needs."
Here, the rabbis see the word "yoreh" as stemming from the root yod-resh-heh, which means to instruct, to teach. The "yoreh," the first rain, teaches us to prepare for the winter, to plaster our roofs, to seal up any holes through which rain might possibly leak. This is our first warning of winter's arrival.
Today, of course, we do not need to gather in fruit as they once did when people would dry their fruit out in the sun. Nonetheless, we can apply the lesson of the "yoreh" to our own time: We, too, must prepare for rains in those areas prone to flooding. We must clean out the canals and reinforce the dirt mounds that prevent flooding. On an individual level, too, the "yoreh" tells us to put away our summer clothes and buckle in for the winter.
Next, the sages describe the "yoreh" as rain that "saturates the ground and waters it right down to its depth, as it is written, 'saturating her ridges abundantly, settling down the furrows thereof, you make her soft with showers, you bless the growth thereof' " (Psalms 65:11). Here the sages associate the word "yoreh" with the root resh-vav-heh, which means to saturate. The first rains fill the cracks in the earth that so anxiously await water. Rain's task is not only to water the exposed earth, but also to saturate down to the depths.
According to the sages' third explanation, the first rain is called "yoreh" because it descends gently, not heavily. Here the sages trace the word "yoreh" to the root yod-resh-heh, which designates something shot, like an arrow, that does not miss its mark (see Exodus19:13 and Rashi's commentary ad loc.).
Rains that fall where they are not needed are liable to be a curse, as the prophet says "And I made it rain upon one city, and did not make it rain upon another city; one field was rained upon, and the field on which it did not rain withered" (Amos 4:7). In the words of the Talmud, "both of them are a curse" (Taanit 7b): when they fall where they are not needed and when they do not fall where they are needed. But when rain falls gently where it is needed, it brings comfort to all.
The root yod-resh-heh evokes other thoughts as well. What if this "shot" of rain causes "the fruit to fall and washes away the seeds"? The Talmud therefore, basing itself upon Yoel (2:23), assures us that the "yoreh" is a blessing: "For it is written, 'Be glad, then, you children of Zion, and rejoice in the Lord your God; for He gives you the former rain in just measure.' "