وَٱلَّذِينَ هُمْ عَلَىٰ صَلَاتِهِمْ يُحَافِظُونَ
Wa a lla th eena hum AAal a s al a tihim yu ha fi th oon a and who guard their prayers [from all worldly intent].
 - Mohammad Asad
and strictly guard their Salah (prayers).
 - Muhammad Farooq-i-Azam Malik
and who are 'properly' observant of their prayers.
 - Mustafa Khattab
And those who are attentive at their worship,
 - Marmaduke Pickthall
And those who guard (the sacredness) of their worship 5697
 - Abdullah Yusuf Ali