http://quran.com/13/28
Sahih International
Those who have believed and whose hearts are assured by the remembrance of Allah . Unquestionably, by the remembrance of Allah hearts are assured."
Muhsin Khan
Those who believe (in the Oneness of Allah - Islamic Monotheism), and whose hearts find rest in the remembrance of Allah, Verily, in the remembrance of Allah do hearts find rest.
Pickthall
Who have believed and whose hearts have rest in the remembrance of Allah. Verily in the remembrance of Allah do hearts find rest!