The Four Keys Held in the Hand of the Holy One

[And the LORD remembered Sarah (Genesis 21:1).] There are four keys: the key of sustenance, and the key of rain, and the key of graves, and the key of barren women; and the four of them are in the hand of the Holy One, blessed be He. The key of sustenance, from where? As it is said, "You open Your hand [and satisfy the desire of every living thing]" (Psalms 145:16). And the key of rain, from where? As it is said, "The LORD will open for you [His good treasure, the heavens, to give the rain of your land in its season]" (Deuteronomy 28:12). And the key of graves, from where? As it is said, "When I open your graves [and bring you up out of your graves]" (Ezekiel 37:13). And the key of barren women, from where? As it is said, "And God remembered Rachel… and He opened her womb" (Genesis 30:22).