Surah An-Najm 53:6

ذُو مِرَّةٍ فَٱسْتَوَىٰ

One of soundness. And he rose to [his] true form

Translation: Saheeh International

Tafsir

possessed of vigour of strength and might or alternatively it dhū mirratin means possessed of a beautiful appearance namely Gabriel peace be upon him; and he stood upright he settled

Excerpt from Tafsir al-Jalalayn, commentary on 53:6, via Quran.com. The reader has the full commentary and 9 more tafsirs.