Surah Al-An'am 6:8

وَقَالُوا۟ لَوْلَآ أُنزِلَ عَلَيْهِ مَلَكٌ ۖ وَلَوْ أَنزَلْنَا مَلَكًا لَّقُضِىَ ٱلْأَمْرُ ثُمَّ لَا يُنظَرُونَ

And they say, "Why was there not sent down to him an angel?" But if We had sent down an angel, the matter would have been decided; then they would not be reprieved.

Translation: Saheeh International

Tafsir

And they say ‘Why has an angel not been sent down to him?’ to Muhammad (s) to confirm his truthfulness; yet had We sent down an angel as they have requested and if they then did not believe the matter that they be destroyed would have been decreed and then they would not be given any respite they would not be given …

Excerpt from Tafsir al-Jalalayn, commentary on 6:8, via Quran.com. The reader has the full commentary and 9 more tafsirs.