Duties assigned to the Angels with regards to human beings
Muslim recorded in his Saheeh that Abu Dharr (radhi allahu anhu) said,
'I heard the Messenger of Allah (sallallahu alahi wa-sallam) say,'When forty-two nights are passed, Allah sends an angel to the nutfah (embryo) and he gives it shape, forming its hearing and sight, its skin, flesh and bones. Then he says, 'O Lord, male or female?' Then your Lord decrees whatever He wills and the angel writes it down.'
[Saheeh Muslim (4/2037, hadeeth no. 2645)]
Four Guardian Angels with every son of Adam
'For each (person), there are angels in succession, before and behind him. They guard him by the Command of Allah.'
[Soorah ar-Ra'd (13): 11]
Imam Ibn Katheer (rahimahullah) writes in the Tafseer of the above verse,
'Allah states that there are angels who take turns guarding each servant, some by night and some by day. These angels protect each person from harm and accidents. There are also angels who take turns recording the good and evil deeds, some angels do this by day and some by night. There are two angels, one to the right and one to the left of each person, recording the deeds. The angel to the right records the good deeds, while the angel to the left records the evil deeds. There are also two angels that guard and protect each person, one from the back and one from the front. Therefore, there are four angels that surround each person by day and they are replaced by four others at night, two scribes and two guards.
An authentic Hadeeth states, 'Angels take turns around you, some at night and some by day, and all of them assemble together at the time of the Fajr and Asr prayers. Then those who have stayed with you throughout the night ascend to Allah, Who asks them, and He knows the answer better than they about you, 'How have you left My servants?' They reply, 'As we have found them praying, we have left them praying.'
[See, Fath al-Baree (13: 426)]
'So where are those who hold back from attending the Fajr Prayer, sleeping (instead) in their beds and not witnessing this great event every night with the angels of the Most Merciful? ...What benefit has this person who refrains from going to the Fajr Prayer and instead prefers sleep gained from his actions? And what benefit has this person who misses out on attending the Asr Prayer, due to laziness, preferring sleep or some other deed, gained from his actions?
It is stated in the hadeeth, 'Whoever misses the Asr Prayer, it is as if he lost his family and wealth.' And in another hadeeth it states: '…then he has nullified his actions.' This means that he has taken the prayer out of its proper time. So if he takes it out of its proper time, he has missed it.'
[See, al-Eeman bil-Malaaikah wa-Athruhu fi-Hayatil-Ummah by Shaikh Salih al-Fawzan]
It is recorded in al-Bidayah wan-Nihayah of Ibn Katheer (1/54) that a man said to Ali ibn Abi Talib (radhi allahu anhu),
'A group from Muraad want to kill you.' He (Ali) said, 'With every man there are angels guarding him from whatever has not been decreed for him. When the decree comes, they move away from him and let it reach him. Your fixed lifespan (decreed by Allah) is a protection for you.'
Therefore, so long as Allah has decreed that an individual will be safe from harms, these angels will protect and guard him, and no human or any other creature will be able to harm him. However, if Allah desires to bring an end to his appointed time, the angels that constantly surround him withdraw themselves from him because they do not refrain from carrying out His Command.
'He is the Irresistible (Supreme), over His slaves, and He sends guardians over you, until when death approaches one of you, Our messengers (angel of death and his assistants) take his soul, and they never neglect their duty.'
[Soorah al-An'am (6): 61]
Allah says about the angels that are appointed to write down the deeds of every person,
'And indeed We have created man, and We know what his own self whispers to him. And We are nearer to him than his jugular vein. (Remember) that the two receivers (recording angels) receive (each human being), one sitting on the right and one on the left (to note his or her actions). Not a word does he (or she) utter but there is a watcher by him ready (to record it).'
[Soorah Qaaf (50): 16-18]
Allah says in another verse,
'But verily, over you (are appointed angels in charge of mankind) to watch you, Kiraman (honorable) Katibeen writing down (your deeds), They know all that you do.'
[Soorah al-Infitaar (82):10-12]
Thus, angels in charge of recording a person's deeds write down everything that he does in his life from the time he reaches the age of puberty to the time when Allah takes his soul in death.
Hence, on the Day of Judgment, each person will find that his book of deeds contains everything that he said or did,
'And We have fastened every man's deeds to his neck, and on the Day of Resurrection, We shall bring out for him a book which he will find wide open. (It will be said to him), 'Read your book. You yourself are sufficient as a reckoner against you this Day.'
[Soorah al-Isra (17): 13-14]
'…the Book (of one's Record) will be placed (in the right hand for a believer in the Oneness of Allah, and in the left hand for a disbeliever in the Oneness of Allah), and you will see the Mujrimoon (criminals, polytheists, sinners, etc.), fearful of that which is (recorded) therein. They will say, 'Woe to us! What sort of Book is this that leaves neither a small thing nor a big thing, but has recorded it with numbers!' And they will find all that they did, placed before them, and your Lord treats no one with injustice.'
[Soorah al-Kahf (18): 49