Eliyahu had orchestrated a three-year drought that had brought the nation to its knees. This had culminated in the decisive religious contest at Mt. Carmel that had exposed the falsity of the Baal, bringing king and country to proclaim faith in God alone. It had been an excruciating process, with Eliyahu living in exile for three years. Indeed, he had succeeding in turning the king around. But now the entire project, this huge educational endeavor, lay shattered, in ruins. It was not Izevel's death threat alone. Izevel's confidence highlighted the understanding that she was in control, and that the transformation of national priorities would be a more arduous, complex, and protracted process. All of this leads to Eliyahu's feeling of dejection and his rejection of his role as a prophet. Unlike Moshe, he is unable to be zealous towards the sinner but to invoke God's mercy on the nation as a whole. 

Courtesy of the Virtual Beit Midrash, Yeshivat Har Etzion