Deuteronomy 28:12

The Lord shall open unto thee his good treasure, the heaven to give the rain. — The Jews have a saying that, “There are three keys in the hand of the Holy One, blessed be He! which He hath not intrusted to the hand of a messenger, and they are these, the key of the rains, the key of birth, and the key of the resurrection of the dead.” The key of the rain, as it is written (Deuteronomy 28:12), “Jehovah shall open to thee His good treasure,” &c. (from the Talmudic treatise, Ta’anith, p. 20, b).