50:17 When the two receivers receive, sitting on the right and on the left.
It is reported that the two angels entrusted with the servant sit like the servant. The one on the right writes his beautiful deeds, and the one on the left writes his ugly deeds. When the servant sleeps, one stands above his pillow, while the other watches over him from his feet. When the servant walks, one goes before him and ones goes behind, both of them protecting him from blights.
It has also been said that the angel of beautiful deeds is changed every day and night, another angel being sent. The wisdom in this is that tomorrow he will have many witnesses for his acts of obedience and beautiful deeds. But the angel of ugly deeds is not changed, so only that angel will know his defects.
The equivalent of this in the Qur'an is found in the verse, "O My servants who have been immoderate against yourselves " [39:53]. In saying "they have been immoderate" God sums everything up, keeping the lid on and without going into detail. He says: O Gabriel, you deliver the revelation, for they have been immoderate, but know not in detail what they have done. O Muḥammad, you recite the revelation, for they have been immoderate, but know not what they have done. Generous Lord, merciful King! He did not want Gabriel to know the sins of the servants and the Messenger to recite their acts of disobedience. How could He then allow Satan to drive the servant away from His threshold?