وَٱذْكُرِ ٱسْمَ رَبِّكَ وَتَبَتَّلْ إِلَيْهِ تَبْتِيلًا
Wa o th kuri isma rabbika watabattal ilayhi tabteel a n But [whether by night or by day,] remember thy Sustainer's name, and devote thyself unto Him with utter devotion.
 - Mohammad Asad
Remember the name of your Rabb and devote yourself to Him exclusively.
 - Muhammad Farooq-i-Azam Malik
'Always' remember the Name of your Lord, and devote yourself to Him wholeheartedly.
 - Mustafa Khattab
So remember the name of thy Lord and devote thyself with a complete devotion--
 - Marmaduke Pickthall
But keep in remembrance the name of the Lord and devote thyself to Him wholeheartedly.
 - Abdullah Yusuf Ali