When the goblet is discovered, Yosef demands that Binyamin become his slave as a punishment. Yehuda, remembering his promise to his father, interposes and offers himself instead, but Yosef refuses. When Hashem brought the universe into existence, if left to itself, Creation would have continued to expand ad infinitum . Thus, when this point was reached, it was enough - the creation did not need to be any larger to evoke man's recognition of the power of the Almighty. Similarly, when a person experiences adversity, it is to purify him and to bring him to recognize his Creator.
Fire consists of two powers - the power to burn, and the power to illuminate.
The Chashmonaim in the days of Chanukah used both of these powers. Fire to sear and eradicate the impurity of the Greeks, and the fire of the Torah to light up the Beis Hamikdash once it had been re-sanctified. A fire to burn out Evil, and a fire to illuminate Good. There is a famous dispute between Beis Shammai and Beis Hillel how to light the Chanukah candles. Beis Shammai says that you start with eight candles on the first night and work down to one on the last, and Beis Hillel says you start with one and work up to eight.