God shows Ezekiel a vision of a valley full of dried-out human bones. He tells Ezekiel to prophesy and bring the bodies back to life. Huh?
So I prophesied as I had been commanded; and as I prophesied, suddenly there was a noise, a rattling, and the bones came together, bone to its bone. I looked, and there were sinews on them, and flesh had come upon them, and skin had covered them; but there was no breath in them. Then he said to me, Prophesy to the breath, prophesy, mortal, and say to the breath: Thus says the Lord God: Come from the four winds, O breath, and breathe upon these slain, that they may live. I prophesied as he commanded me, and the breath came into them, and they lived, and stood on their feet, a vast multitude. (37:7-10)
No, this isn't God's sneak preview of the series finale of "The Walking Dead." It's first and foremost a prophecy about the House of Israel. After the Babylonian invasion and its exile, the House of Israel seemed totally dead and defeated. But now, God says they'll come back from the dead with a new covenant with God. After the exile, the population had been pretty much decimated, so God makes sure there will be a "multitude" that returns and gives witness to his amazing glory.
At the same time, this vision also hints of an actual resurrection from the dead—an idea that would prove to be important both to Christianity and to later Judaism. The Hebrew Bible doesn't talk too much about the afterlife. But Ezekiel and Isaiah contain images relating to life after death, and in the Book of Daniel there's an unambiguous description of the resurrection of the dead. Given what this book is about, though—the destruction and restoration of the nations of Judah and Israel—it's doubtful that Ezekiel meant anything more than that at the time.