Quran 15:38 from Surah Al-Hijr on Divine Marvels.
إِلَىٰ يَوۡمِ ٱلۡوَقۡتِ ٱلۡمَعۡلُومِ
English translation: Till the Day (of) the time well-known
Transliteration: ila yawmi al-waqti al-ma'lumi