Rain is symbolic of our relationship with God. The second paragraph of Shema states that if the People of Israel love and serve God wholeheartedly, they will be provided with ample rain for the Land of Israel. An absence of rain is presented as a punishment for not following God’s law, and rain in its season is an indication of Israel following God's commandments. Yirmiyahu chastises the nation for neglecting to follow God’s commandments out of love, and for worshipping Him out of fear since He is One who provides rain in the proper season.
Rain reminds us of our dependence upon God. The Land of Israel, unlike Egypt's Nile, does not have the large, constant water source. Israel needs rain, and its people must look skyward for water to drink.
But rain is not always a sign of blessing: When the prophet Shmuel rebuked the nation for requesting a king, he offers them a sign: a thunderstorm during the wrong season, which ruins their crops. In the story of Noah, rain catastrophically pours until the waters cover the earth in an enormous, devastating flood.
During the reign of Ahav, the prophet Eliyahu proclaims a drought, when he sees the people straying from the worship of God. Eliyahu’s announcement of the coming rainfall appears only after he rouses the people to affirm their belief in God, following his showdown with the Baal prophets.
Zekhariah describes the future notion of all the nations gathering to Jerusalem to celebrate the Sukkot festival. If they refuse to come, they will not be blessed with rain.
In the book of Yoel, an existential crisis looms, causing the people fast and beg God to save them. God has responds with a merciful call for Zion to rejoice, as He will cause the ideal type of rain to fall in its time and for the full season, leading to an abundance of grain, wine and oil, and to the recognition that God dwells within Israel.
We hope for the fulfilment of Yehezkel’s lyrical prophecy of redemption wherein God will gather in His scattered flock to thrive serenely in the Land, and send rains of blessing in their season.