Surah Ash-Shu'ara 26:23

قَالَ فِرْعَوْنُ وَمَا رَبُّ ٱلْعَـٰلَمِينَ

Said Pharaoh, "And what is the Lord of the worlds?"

Translation: Saheeh International

Tafsir

Pharaoh said to Moses ‘And what is “the Lord of the Worlds” ’ the One Whose Messenger you say you indeed are? In other words what exactly is He? And since there is no way for creation to know the true nature of God but only to know Him through an articulation of His attributes Moses blessings and peace be upon him …

Excerpt from Tafsir al-Jalalayn, commentary on 26:23, via Quran.com. The reader has the full commentary and 9 more tafsirs.