זוהר שמות — דף כח ע”ב

Rabbi Elazar refutes those who deny resurrection of the dead: if the Holy One transformed a dry stick into a living creature, all the more so will He revive those who observed the Torah. One bone remains underground, imperishable, and at the resurrection the Holy One will soften it like leaven in dough and the body will be reconstituted. Aaron struck the Nile because all Egyptian waters flow from it, and it was their primary object of worship that had to be struck first. The firmament holding sun and moon is the reservoir of the upper waters that irrigates all the lower world.