Quran 68:3 from Surah Al-Qalam on Divine Marvels.
وَإِنَّ لَكَ لَأَجۡرًا غَيۡرَ مَمۡنُونٖ
English translation: And indeed for you surely (is) a reward without end
Transliteration: wa-inna laka la-ajran ghayra mamnunin