What Is the Nature of the Soul in Islam?
Question

With regard to Islam, what is the soul? For instance, who created the soul, and what limitations does it have?
Praise be to Allah.The Creation of the Soul
Allah is the Creator of all things, and the soul is something that has been created just like everything else. The knowledge about its true essence is something that belongs exclusively to Allah, may He be Glorified and Exalted.
Allah has kept this knowledge exclusively to Himself, as is stated in the Hadith of `Abdullah ibn Mas`ud (may Allah be pleased with him), who said: Whilst I was with the Prophet (peace and blessings of Allah be upon him) on a farm, and he was resting on a palm branch stripped of its leaves, the Jews passed by, and some of them said to others, Ask him about the soul. Some of them said, What urges you to ask him about it? Others of them said, Don’t ask him in case he says something you dislike. But they said, Ask him, so they asked him about the soul. The Prophet (peace and blessings of Allah be upon him) kept quiet and did not respond to them, and I knew that he was receiving Revelation, so I stayed where I was. When the Revelation of the verse was complete, he said (interpretation of the meaning): {And they ask you [O Muhammad] concerning the [the soul]. Say: The Ruh: it is one of the things, the knowledge of which is only with my Lord. And of knowledge, you (mankind) have been given only a little.} [Al-Isra’ 17:85] (Narrated by Al-Bukhari)
The Ruh (soul or spirit) has been described by Allah in His Book and by the Messenger (peace and blessings of Allah be upon him) in his Sunnah, and various verbs and adjectives have been used in conjunction with the word Ruh, such as seizing or grasping, taking (as in death), it may be fettered or shrouded, it comes and goes, it goes up and comes down, it may be pulled out like a hair being pulled out of dough.
It is obligatory (in Islam) to believe in these attributes which are narrated in the two Revelations (i.e., the Quran and Sunnah), and also to realise that the soul is not like the body.
How the Soul Is Breathed into Human Life
Allah created Adam and breathed the soul into him, as is stated in the Quran and in the Hadith of the Prophet (peace and blessings of Allah be upon him): When Allah created Adam and breathed the soul into him, he sneezed and said Al-Hamdulillah (Praise be to Allah). He praised Allah by His permission. Then his Lord said to him, May Allah have mercy on you, O Adam. Go to those angels, to a group of them who are sitting, and say, As-Salamu `Alaykum (peace be upon you). They said, Wa `Alayka As-Salam wa Rahmatullah (and upon you be peace and the Mercy of Allah). Then he went back to his Lord, who said, This is your greeting and the greeting of your descendants amongst themselves. (Narrated by At-Tirmidhi, and he classed it as sound, Sunan At-Tirmidhi, 3290)
Allah sends the angel to breathe the soul into the foetus as was reported by `Abdullah ibn Mas`ud (may Allah be pleased with him), who said: The Messenger of Allah (peace and blessings of Allah be upon him), who is the most truthful (of human beings) and his being truthful (is a fact) told us: The constituents of one of you is gathered in his mother’s womb for forty days, then it becomes a clot of blood within another period of forty days. Then it becomes a lump of flesh, and forty days later, Allah sends His angel to it to breathe into it the soul. The angel comes with instructions concerning four things, so the angel writes down his livelihood, his death, his deeds and whether he will be doomed or blessed. (Narrated by Muslim, 1528)
The Journey of the Soul after Death
The soul of the deceased is taken from the ends of the toes towards the top of the body, and when it reaches the throat, the death rattle sounds in the throat of the person who is about to die, and his eyes glaze over and roll upwards. Umm Salamah (may Allah be pleased with her) said: The Messenger of Allah (peace and blessings of Allah be upon him) entered upon Abu Salamah (after he had died) and his eyes were open, so he closed them then said, When the soul is taken, the eyes follow it. (Narrated by Muslim, 1528)
The soul is met by the angels. The Prophet (peace and blessings of Allah be upon him) said: The angels met the soul of a man from among the people who came before you, and said, Did you do anything good? He said, ‘I used to tell my employees to postpone collection of payment or to let off anyone who was in difficulty. So it was said, ‘Let him off.’ (Narrated by Al-Bukhari, 1935)
The soul is taken up to heaven by two angels after it is taken (i.e., after a person dies), as was reported in the Hadith of Abu Hurayrah (may Allah be pleased with him) who said: When the soul of the believer is taken, it is met by two angels who take it up (The narrator said: then he mentioned its good fragrance and scent of musk). The people of heaven say, ‘A good soul that has come from earth, may Allah bless you and the body in which you used to dwell. Then they take it up to its Lord, may He be Glorified and Exalted, then He says, Roam with it until the end of the world.’ When the disbelievers soul comes out (the narrator mentioned its putrid smell and curses). The people of heaven say, ‘An evil soul that has come from earth, then it is said, Roam with it until the end of the world.’ Abu Hurayrah (may Allah be pleased with him) said: then the Messenger of Allah (peace and blessings of Allah be upon him) put a piece of cloth over his nose, like this. (Narrated by Muslim, 5119)
More information about how the soul comes out (at death) was reported in the Hadith of Imam Ahmad (may Allah have mercy on him) from Al-Bara’ ibn `Azib (may Allah be pleased with him) who said:
We went out with the Prophet (peace and blessings of Allah be upon him) for the funeral of a man from among the Ansar, and we reached the grave whilst it was still being dug. The Messenger of Allah (peace and blessings of Allah be upon him) sat down and we sat down around him, and it was as if we had birds on our heads. In his hand was a stick with which he was scratching in the earth. He raised his head and said, ‘Seek refuge with Allah from the punishment of the grave’, two or three times.
Then he said, ‘Verily, when the believing slave is about to depart this world and enter the Hereafter, there come down to him angels from heaven with white faces, as if their faces are the sun. They bring with them one of the shrouds of Paradise and some of the perfume of Paradise. They sit with him as far as the eye can see.
Then the Angel of Death (peace be upon him) comes to him and sits by his head and says, ‘O pure soul, come out to the forgiveness and pleasure of Allah’. Then his soul comes flowing out like a drop of water flowing from a cup. Then he takes the soul, and no sooner does he seize it but they take it and place it in that shroud and perfume. Then out of it comes the most excellent fragrance of musk to be found on the face of the earth. Then they ascend with it and they do not pass by any group of angels but the angels ask, ‘Who is this pure soul?’ and they reply, ‘It is So and so the son of So and so’ using the best names by which he was known on earth.
Then they bring it to the lowest heaven, and ask for it to be opened, and it is opened for him. Those who are of high rank in each heaven accompany it until they approach the next heaven, and so it goes until it reaches the seventh heaven.
Then Allah, may He be Glorified and Exalted, says: ‘Record the book of My slave in `Illiyin (the highest heaven) and take him back to the earth, for I created them from it, and I shall return them to it, then I shall take them out from it again.’
Then his soul is returned to his body and two angels come and make him sit up, and ask him, Who is your Lord. He says, Allah. They ask, ‘What is your religion?’ He says, ‘My religion is Islam.’ They ask, ‘Who is this man that was sent amongst you?’ He says, ‘He is the Messenger of Allah (peace and blessings of Allah be upon him).’ They ask him, ‘What knowledge do you have?’ He says, ‘I read the Book of Allah and I believed in it.’
Then a voice will call out from heaven, ‘My slave has spoken the truth. Prepare for him a bed from Paradise and give him clothes from Paradise, and open for him a door to Paradise.’ And he will feel its breeze and smell its fragrance, and his grave will be widened for him as far as his eye can see.
Then a man with a handsome face, beautiful clothes and a pleasant fragrance will come to him and say, Good news! This is the day that you were promised. He will say, ‘Who are you?’ You face looks as if it brings good news. He will say, ‘I am your good deeds.’ (The deceased) will say, ‘O Lord, let the Hour come so that I may see my family and my wealth again.’
When the disbelieving slave is about to depart this world and enter the Hereafter, there come down to him angels from heaven with black faces, bringing with them sackcloth. They sit with him as far as the eye can see. Then the Angel of Death comes to him and sits by his head and says, ‘O evil soul, come out to the wrath and anger of Allah.’ Then his soul disperses in his body and is dragged out like a skewer being pulled out of wet wool. Then he takes the soul, and no sooner does he seize it but they take it and place it in that sackcloth. Then out of it comes the most putrid stench of rotten flesh to be found on the face of the earth.
Then they ascend with it and they do not pass by any group of angels but the angels ask, ‘Who is this evil soul?’ and they reply, ‘It is So and so the son of So and so’ using the worst names by which he was known on earth.
Then they bring it to the lowest heaven, and ask for it to be opened, and it is not opened for him. Then the Messenger of Allah (peace and blessings of Allah be upon him) recited (interpretation of the meaning): {For them the gates of heaven will not be opened, and they will not enter Paradise until the camel goes through the eye of the needle.} [Al-Araf 7:40]
Then he said, Then Allah, may He be Glorified and Exalted, says: Record the book of My slave in Sijjin (the lowest Hell) in the lowest earth. Then his soul is cast down. Then he recited (interpretation of the meaning): {and whoever assigns partners to Allah, it is as if he had fallen from the sky, and the birds had snatched him, or the wind had thrown him to a far off place.} [Al-Hajj 22:31]
He said, Then his soul is returned to his body and two angels come and make him sit up, and ask him, ‘Who is your Lord.’ He says, ‘Oh, oh, I don’t know.’ They ask, ‘What is your religion?’ He says, ‘Oh, oh, I don’t know.’ They ask, ‘Who is this man that was sent amongst you?’ He says, ‘Oh, oh, I don’t know.’
Then a voice will call out from heaven, He is lying. Prepare for him a bed from Hell and open for him a door to Hell. And he will feel its hot winds and smell its stench, and his grave will be constricted for him until his ribs interlock.
Then a man with an ugly face, ugly clothes and a horrible stench will come to him and say, ‘Bad news!’ This is the day that you were warned about. He will say, ‘Who are you?’ You face looks as if it brings bad news. He will say, ‘I am your evil deeds.’ (The deceased) will say, ‘O Lord, do not let the Hour come!’ (Musnad Al-Imam Ahmad, 17803; this is an authentic Hadith.)
The Soul and the Day of Judgment
At the end of time, Allah will send a wind which will take the soul of every believer, as was reported in the Hadith of An-Nawwas ibn Sam`an (may Allah be pleased with him), who said: The Messenger of Allah (peace and blessings of Allah be upon him) mentioned (the coming of the Dajjal [Antichrist] and the descent of `Isa [Jesus], peace be upon him, and the good life and happiness of mankind at the time of Jesus and afterwards). He said, ‘And whilst the people are living like that, Allah will send a good wind which will seize them under the armpits and will take the soul of every believer and every Muslim. The evil people will remain and they will behave like donkeys, then the Hour will come upon them.’ (Narrated by Muslim, 5228)
When people sleep (and sleep is the lesser death), the soul is taken, but not completely, so the sleeper is still alive. Allah says (interpretation of the meaning): {It is Allah Who takes away the souls at the time of their death, and those that die not during their sleep, He keeps those (souls) for which He has ordained death and sends the rest for a term appointed. Verily, in this are signs for a people who think deeply.} [Az-Zumar 39:42]
The Messenger of Allah (peace and blessings of Allah be upon him) advised the Muslim, when he lies down to sleep, to say: Bismika Rabbi wada`tu janbi wa bika arfa`uhu wa in amsakta nafsi farhamha wa in arsaltaha fahfadh-ha bima tuhfadhu bihi `ibadika As-salihin (In Your name, my Lord, I lie down, and in Your name I rise. If You should take my soul then have mercy on it, and if You should return my soul then protect it as You protect Your righteous slaves).
When the Muslim wakes up, he should say, Al-hamdulillah alladhi `afani fi jasadi wa radda `alayya Ruhi wa adhina li bi dhikrihi (Praise be to Allah Who has restored to me my health and returned my soul and has allowed me to remember Him). (Narrated by At-Tirmidhi, 3323, who classed it as sound)
These are a few of the verses and authentic Hadiths which describe the soul. Maybe you will find in them information that will guide you to the way of truth, the Religion of Islam. Thank you for your question.
And Allah knows best.