There are two points of view in the Talmud as to whether this prophecy (Ezekiel 37 Dry Bones) is a parable or whether the bones in the valley actually came to life (Sanhedrin 92b). In either case, it is understood by the commentators as a source of hope for Israel in its exile and as a reinforcement of the principle that the dead will come to life again in Messianic times:(1)
For more information on how important belief in a resurrection was check out the Talmud Resurrection Notes.
For a closer look at Ezekiel's prophecy please read Valley Of The Dry Bones.
1). ArtScroll Stone Edition Tanach p.1295.