Muslim scholars agree that angels record what one intends to do and what is in one’s mind. In short, they know the internal matters of the hearts of man. It is important to note that angels know these matters after they have actually taken place; hence, they never refer to the Unseen. However, there are two opinions concerning the way in which Angels know human intentions. Firstly, bad intentions have an odious smell whereas good intentions have a good smell, and these are the things, which Angels are able to distinguish. Secondly, Allah makes known the intentions behind man’s deeds to the Angels after they have already taken place. Accordingly, this does not contradict the fact that Angels do not know the Unseen.
About the Qur’anic verse that reads: “Lo! There are above you guardians, Generous and recording, who know (all) that you do.” (Al-‘Infitar: 10-12) Al-Qurtubi explained it saying: “Angels are able to know man’s deeds.” As well as this, it is said: “Angels not only know what a person does, but what he intends to do.” Sufyan was asked: “How do Angels know if a person has a bad or a good intention?” He replied: “When a person intends to do a good deed, Angels perceive the smell musk coming out of him, whereas if his intention is evil, they smell a bad odor.” Ibn Jareer At-Tabari, the great Muslim exegete, explained the verse: “Who know (all) that you do,” by saying: “The appointed Angels over mankind are able to distinguish a good deed from a bad one.”
The Prophet (Peace and blessings be upon him) is reported to have said: “Allah ordered (the appointed Angels over you) that good and bad deeds are to be written, and He then showed (the way) how (to write). If somebody intends to do a good deed and he does not do it, then Allah will write for him a full good deed (in his account with Him); and if he intends to do a good deed and actually does it, then Allah will write for him (in his account) with Him (its equal reward ) from ten to seven hundred times, to many more times: and if somebody intended to do an evil deed and he does not do it, then Allah will write a full good deed (in his account) with Him, and if he intended to do it (a bad deed) and actually did it, then Allah will write one bad deed (in his account).” There is another narration to the same effect, that the Angels said to Allah: “O Allah, this is Your servant and he intends to do a bad deed, while Allah is more aware about that. Allah shall say: ‘Watch him, and record it if he does it,’” Commenting on this Hadith, An-Nawawi quoted Abu Ja`far At-Tahawi (May Allah have mercy on him) as having said: “According to these Hadiths the Angels appointed over human beings record man’s intentions, contrary to those who say that Angels only record apparent deeds.” Ibn Hajar commented on the abovementioned Hadith saying: “It proves that Angels are able to know human intentions either as revealed by Allah or by having special knowledge which He granted them.” The first view is supported by that which is narrated from Abu `Imran al-Juni that: “An Angel is ordered to record so and so. The Angel says there is no deed to record, so Allah will tell him that he intended to do it.” It is also argued that the Angel is able to smell the bad smell of evil deeds and the good smell of good deeds.
About the verse: “Lo! There are above you guardians”, the late Sheikh Ibn `Uthaymeen, a prominent Saudi Muslim scholar, (may Allah shower mercy on his soul) said: “Each human being has an appointed Angel who records all his deeds.” Allah says: “He utters no word but there is with him an observer ready.” (Qaf: 18) Nevertheless, these Angels are known for their generosity in the sense that they are never unfair to any one. Consequently, they record only what they see or hear. Moreover, Angels are able to know the intentions of man, and in this regard, the Prophet (Peace and blessings be upon him) said: “If somebody intends to do a good deed and he does not do it, then Allah will write for him a full good deed, and if he intends to do a bad deed and he does not do it, then Allah will write a full good deed for him.” Hence, a person is rewarded for refraining from doing a bad deed”