38:81

إِلَىٰ يَوْمِ الْوَقْتِ الْمَعْلُومِ

Transliteration:

Ila yawmi alwaqti almaAAloomi

Word by Word:

Until (the) Day (of) the time well-known."

Translations:

till the Day the time whereof is known [only to Me]."

"Till the Day of the Time Appointed."

Until the day of the time appointed.

Till the day of the time made known.

Until the Day of the time well-known."