Rabbi Yochanan says there are three keys in the hands of the Holy
One!--blessed be He!--which He never intrusts to the disposal of a
messenger, and they are these:--(1.) The key of rain, (2.) the key of
life, and (3.) the key of reviving the dead. The key of rain, for it is
written (Deut. xxviii. 12), "The Lord shall open unto thee His good
treasure, the heaven to give the rain unto thy land in season;" the key
of life, as it is written (Gen. xxx. 22), "God hearkened unto her, and
opened her womb;" the key of reviving the dead, for it is written (Ezek.
xxxvii. 13), "When I have opened your graves, and brought you up out of
your graves, and shall put my spirit in you, and ye shall live," etc.
THE TALMUD, _Taanith_, fol. 2, cols, 1, 2.