The Apartments - 49:13
O people, We created you from a male and a female and divided you into races and tribes so that you may know one another. The most worthy of you with Allah is the most virtuous. Allah is All-Knowing, All-Knowing.
Why did Allah create everything in pairs?
Council/42:11
It is He Who created the heavens and the earth by splitting them. He created mates for you from among yourselves, and He created livestock in pairs. Thus He produces you therein. There is nothing like Him. He is the Hearing, the Seeing.