Al-Khashiun

Al-Baqara [2:45]

And seek help in patience and As-Salât (the prayer) and truly it is extremely heavy and hard except for Al-Khâshi'ûn [i.e. the true believers in Allâh - those who obey Allâh with full submission, fear much from His Punishment, and believe in His Promise (Paradise,) and in His Warnings (Hell, )].