15:99
وَاعْبُدْ رَبَّكَ حَتّٰى یَاْتِیَكَ الْیَقٖینُ
WaoAAbud rabbaka hatta yatiyaka alyaqeenu
Translations
And worship your Lord until there comes to you the certainty (death)
Saheeh International
And serve thy Lord till the Inevitable cometh unto thee
Marmaduke Pickthall