وَمِن كُلِّ شَيْءٍ خَلَقْنَا زَوْجَيْنِ لَعَلَّكُمْ تَذَكَّرُونَ
[51:49]
And of everything We have created pairs that you may be mindful.
And of every thing We have created pairs: That ye may receive instruction.
And all things We have created by pairs, that haply ye may reflect.