(Ad-Dukhan) 44 : 38
وَمَا خَلَقْنَا السَّمَاوَاتِ وَالْأَرْضَ وَمَا بَيْنَهُمَا لَاعِبِينَ
And We have not created the heavens, earth, and all things in between them as idle play.
See explanation 3:190-191; 23:51-53; 39:5.