Surah Al-An'am 6:9

وَلَوْ جَعَلْنَـٰهُ مَلَكًا لَّجَعَلْنَـٰهُ رَجُلًا وَلَلَبَسْنَا عَلَيْهِم مَّا يَلْبِسُونَ

And if We had made him [i.e., the messenger] an angel, We would have made him [appear as] a man, and We would have covered them with that in which they cover themselves [i.e., confusion and doubt].

Translation: Saheeh International

Tafsir

And had We appointed him the one who is sent down to them an angel We would assuredly have made him the angel a man that is We would have sent him in the form of a man so that they would be able to see him since no human being is capable of seeing an angel; …

Excerpt from Tafsir al-Jalalayn, commentary on 6:9, via Quran.com. The reader has the full commentary and 9 more tafsirs.