Surah Taha 20:17

وَمَا تِلْكَ بِيَمِينِكَ يَـٰمُوسَىٰ

And what is that in your right hand, O Moses?"

Translation: Saheeh International

Tafsir

And what is that that happens to be in your right hand O Moses?’ the interrogative is meant as an affirmative but it is expressed as an interrogative in order that the miracle to be manifested in it be shown as consequent upon it.

Excerpt from Tafsir al-Jalalayn, commentary on 20:17, via Quran.com. The reader has the full commentary and 9 more tafsirs.