The Quran says that every person's words and deeds are being recorded by angels. (50:17) This was earlier a matter of belief. But today this has become a known and an understandable fact. For example, CCTV cameras are put up at a number of places and make a full video and audio recording of events. These cameras serve as an example of how the angels are recording people's actions, which will be shown to them on the Day of Judgment, so that they are not in a position to deny what they did.