Al-Lail • EN-AL-JALALAYN
﴿ وَٱلنَّهَارِ إِذَا تَجَلَّىٰ ﴾
“and the day as it rises bright!”
and by the day as it unveils as it is revealed and becomes manifest idhā ‘as’ in both instances is an absolute adverbial operated by the verbal action of the oath