While he was in the highest part of the horizon:
Gabriel appeared in stately form, perhaps
towering above the Mountains of Light (see C. 31).
Istawa in verse 6 translated “appeared”, means literally
“mounted” or “ascended”, or “set himself to execute a
Yusuf Ali, Abdullah. Translation and Commentary of the Quran. (surah 53 verse 7 Quran Arabic with English Translation & Commentary (Tafsir) by Abdullah Yusuf Ali, Free Download (quran4u.com)