The Last Test Before Moshiach
History shall repeat itself, said Rabbi DovBer of Mezeritch, but with one significant difference.
Some twenty-seven hundred and thirty years ago, one of the most dramatic events in Jewish history took place atop Mount Carmel in northern Israel.
The people of Israel were torn between their allegiance to G-d and the dominating Baal culture espoused by King Ahab and his queen, Jezebel. The prophet Elijah challenged Ahab and the "prophets" of the pagan gods Baal and Aseirah to a contest before the entire nation.
When all had assembled on the summit of Mount Carmel, Elijah approached the entire nation and said to them: "How long will you go on wavering between both sides? If G-d is the Lord, follow Him, and if Baal is, follow him." And the people answered him not a word.
Said Elijah to the nation: "I alone remain a prophet of G-d, while the Baal's prophets are four hundred and fifty men. Let there be given us two bullocks; and let them choose one bullock for themselves, and butcher it and place on the wood pile, and put no fire underneath. I will prepare the other bullock, lay it on the wood pile, and put no fire underneath.
"Call on your gods and I will call on G-d, and the god who shall answer with fire, he is the true G-d." And the entire nation
responded: "It is good, [what you propose]."
... [The prophets of Baal] prepared their bullock. And they called upon Baal from morning till noon, saying, "Baal! Answer us!" But there was no voice, no response. And they capered about the altar they had made ... And Elijah mocked them, saying, "Cry aloud, to this god of yours. Perhaps he is conversing, or meditating, or off on a trip; perhaps he is asleep and must be awakened..."
Come evening, Elijah the Prophet approached [G-d] and said: "G-d, the G-d of Abraham Isaac and Israel, let it be known this day that You are G-d in Israel and I am Your servant, and that I have done all these things at Your word. Answer me, O G-d, answer me, so that this people may know that You are the G-d, for it is You who has caused their hearts to turn away from You."
And the fire of G-d fell, and consumed the offering, the wood, and the stones and earth [of the altar], and licked up the water that was in the trench. The entire nation saw, and fell upon the faces. And they said "G-d is the G-d! G-d is the G-d." 
Said Rabbi DovBer,  the Maggid of Mezeritch:
Just prior to the coming of Moshiach, the contest of the "Two Bullocks" will again take place. Again, the people of Israel will be polarized between faith in G-d and the prevailing "gods." Again, a lone prophet of G-d will challenge the many and the powerful. Again, a nation will await a sign from Above as to where to place their loyalty.
The showdown atop Mount Carmel will repeat itself, but with one significant difference: this time, the fire will fall on the side of the Baal. This time, the prophet of G-d will be ignored, while a fire from heaven will endorse the prophets of Baal. This time, those who call upon the true G-d of Israel will be mocked and derided, as their cries go unheeded and their prayers unanswered.
Just prior to the coming of Moshiach, the Jewish people will face the greatest test of faith in history. Those who will persist with their faith in G-d and His prophets despite all, will merit to bring the complete and ultimate redemption.
 "Said Rabbi Elazar: Elijah spoke harshly to G-d, saying `it is You who has caused their hearts to turn away from You.'
Said Rabbi Shmuel bar Rabbi Yitzchak: We find that G-d admitted that he was right, in saying (Micha 4:6) `I have afflicted' --- I have caused them to sin, by creating the evil inclination (Talmud, Brachot 31b; Rashi, ibid.).
The Midrash interprets the Elijah words thus: If you do not answer me, than I, too, will turn against You, and say that it is your doing that their hearts have turned away from You
(cited by Rashi in his commentary on I Kings 18:37).
 I Kings 18:21-39.
 Leader of the chassidic movement in the years 1761-1772.