If day and night can unite, surely we can all unite and become one family. We may have our differences, and some of us may be as different as night and day; however, if we rise above our egos and seek to benefit others instead of ourselves, we'll connect with each other in mutual concern and responsibility.
It is written, "Do you not see that Allah causes the night to enter the day and causes the day to enter the night ..." (Quran 31:29, Sahih)
YouTube Video: Day And Night By Pixar