Commentaire sur Le Deutéronome 11:14

ונתתי מטר ארצכם I WILL GIVE THE RAIN OF YOUR LAND [IN ITS SEASON] — You will then have done what devolved upon you, I, too, shall do what devolves upon Me (Sifrei Devarim 41:29; cf. Rashi on Deuteronomy 26:15).

ונתתי מטר ארצכם בעתו, “I will give the rain for your land at its appropriate time.” At the hours when it is most beneficial for newly seeded fields. You will be pleased with the timing of the rain, which, according to our sages in Taanit 22 and 23 will descend at night when it does not interfere with any of your activities. In Leviticus 26,3 the Torah words this blessing somewhat differently, writing “ונתתי גשמיכם בעתם, “I will give your rains at their respective seasons.” Our sages interpret the wording there to mean that the rain will neither be sparse nor excessive. Too much rain soaks the earth so that it does not produce fruit. Another meaning of these words is that the word בעתם, refers to the nights from Tuesday to Wednesday and on Friday nights, periods when everyone is at home. We have a tradition that during the period of Rabbi Shimon ben Shetach this blessing was fulfilled and the rains in Israel descended only on these two nights of the week. As a result, the wheat kernels were as big as kidneys and the barley as big as the pits of the olives, and lentils grew to the size of golden dinars. Our sages used this period to illustrate to what extent sins by the people can reduce the fertility of the Holy Land. They used Jeremiah 5,25 to illustrate their point. The prophet wrote: “it is your iniquities that have diverted these things, your sins have withheld the bounty from you.” We also find that during the reign of Herod when the people were busy with major renovations of the Temple, rain descended only at night so as not to interfere with the work of restoring and enlarging the Temple. On the morning following such rain, the clouds would disperse quickly, the sun would shine and work could proceed without impediment. The people would rise at an early hour and go to work at the Temple site.

You fulfill your obligation, etc. Rashi is answering the question: Why does it say regarding this commandment there is so much reward, “I will provide the rain of your land in its time, fall rain and spring rain, etc.”? Yet above in Parshas Bechukosai (Vayikra 26:4) Scripture only writes, “I will provide your rain in their proper time”! Rashi answers: You fulfill your obligation, etc. In other words, you shall fulfill your obligation and you need not do more than this — to keep My commandments out of love. As it is written, “To love Adonoy ... and to serve Him, etc.” therefore I shall fulfill my obligation and pay you abundant reward. (Re”m).