In the second aliyah (section) of Parshas Bo, the plague of darkness is discussed. The Egyptians experienced a thick darkness, while the Jews had light even amongst the Mitzriyim. This separation is apparent throughout the Makkos, except for the final plague, Makkas Bechoros. Through Yetzias Mitzrayim, Bnei Yisroel are shifting to a distinct existence as a nation. They will no longer experience other-worldly occurrences in which light and darkness can serve together; rather, they will be part of the laws of nature, with entire units affected by the same elements.