﴿ وَمِن كُلِّ شَىْءٍ خَلَقْنَا زَوْجَيْنِ لَعَلَّكُمْ تَذَكَّرُونَ ﴾

“And in everything have We created oppos­ites, so that you might bear in mind [that God alone is One].”

And all things We have created by pairs) in the earth, (that haply ye may reflect) on the creation of Allah.