Surah Al-Haqqah 69:39
وَمَا لَا تُبْصِرُونَ
And what you do not see
Translation: Saheeh International
Tafsir
and all that you do not see of them in other words I swear by all creatures
Excerpt from Tafsir al-Jalalayn, commentary on 69:39, via Quran.com. The reader has the full commentary and 9 more tafsirs.