שמות ט ,לג : וַיַחְדְלוּ הַקֹלוֹת וְהַבָרָד וּמָטָר לֹא־נִתַךְ אָרְ צָה:
The Baal haTurim observes that the word נתך occurs three times in Tanach: (1) here where the rain did not reach the ground; (2) Shmuel 21,10 regarding the executed sons of Shaul that remained hanging until the rain came down; and (3) Yirmiyahu 42, 18, “Just as My anger and My wrath were poured down upon the people of Yerushalyaim.”
This indicates that the prayers of the righteous can withhold the rain. The rain stopped in mid-air in response to the prayer of Moshe. Also, the righteous can cause the rain to fall as did Dovid’s prayers (After a famine of three years, HaShem told Dovid it was due to the house of blood of Shaul who had killed the Givonim. Dovid had handed over seven of Shaul’s descendants to be hanged by the Givonim to avenge the death of seven Giveonim that had be killed in that incident. The bodies remained until they received a heavenly sign of forgiveness to the Jews in the form of rain as a result of prayers of Dovid.) Similarly HaShem will atone for Yerushalayim in response to the prayers of the righteous.
