“Order your companions to watch their tongues, abandon their animosity towards religion, and strive in worshipping God. Tell them to say their obligatory prayers well whenever they prepare to say their prayers. Tell them to completely perform each part of the prayer in bowing down and prostrating, and not think about worldly affairs. I have heard Imam Sadiq (a.s) say that the Angel of Death looks at every believer's face at the time he says his obligatory prayers.”