In Islamic tradition the two kiraman katibin (Arabic: كراماً كاتبين "honourable scribes"), are two angels called Raqib and Atid, believed by Muslims to record a person's actions, thoughts and feelings. Whether a person is sent to Jannah (paradise) or Jahannam (hell/purgatory) is not, however, dependent on whether good deeds outweigh bad deeds; but is ultimately up to Allah's mercy upon a believer. The Quran refers to them in two places, in 50:16-18 and by name as 'Noble Recorders' in 82:10-12.
The work of the Kiraman Katibin is to write down and record every action, thought, or feeling a person has each day. One angel figuratively sits on the right shoulder and records all good deeds, while another sits on the left shoulder and records all bad deeds.
The Book in which the angels are writing is the cumulative record of a given person's deeds. After that person's death, it is said that on the Day of Judgement each person will be confronted with this record, and the two angels will be present to tell God of what the person did.
It is recorded that Muhammad once said, "The (scribe) on the left hand raises his pen (i.e., delays writing) for six hours (this may refer to six hours of 60 minutes as measured by astronomers, or it may refer to short periods of time during the day or night, according to Lisan al-'Arab) before he records the sinful deed of a Muslim. If [the Muslim] regrets it and seeks God's forgiveness, the deed is not recorded, otherwise it is recorded as one deed." A further respite is granted after the deed has been recorded; up until the moment before death approaches, one is able to repent and ask for forgiveness.
Muhammad(saw) also stated: "After the death of the Muslim, they soar to the heaven and seek permission to live there, but Almighty God turns down their request saying, 'My Heavens are full of Angels who are constantly engaged in Glorifying Me'. Then they will Reply, 'Your creation has filled the earth, constantly glorifying You.' Thereafter, Almighty God will command them to stand at the graveside of the Muslims and the servants of Almighty God to recite "Glory be to God" and prayers, and the reward of which is then bestowed upon the deceased person".
These angels are not guardian angels, called in Islamic tradition the mu'aqqibat "followers" (Q.13.10-11). According to many Muslims, each human has two guardian angels, in front and behind him, while the two recorders are located right and left.