Surah At-Takwir 81:23

وَلَقَدْ رَءَاهُ بِٱلْأُفُقِ ٱلْمُبِينِ

And he has already seen him [i.e., Gabriel] in the clear horizon.

Translation: Saheeh International

Tafsir

For verily he Muhammad (s) saw him Gabriel in the form in which he was created on the clear horizon the highest one towards the east;

Excerpt from Tafsir al-Jalalayn, commentary on 81:23, via Quran.com. The reader has the full commentary and 9 more tafsirs.