Allah created the Nafs (self or ego) and was the one who categorized it into different kinds in the Qur’an. The first is called “the constant commanding soul (commanding the self to evil)” (12:53), in arabic this is Al Nafs Al-Ammara, elsewhere Allah took an Oath by the second, Nafs al Lawwama, “and I swear by the constant reproachful soul (the person who is correcting himself after his mistakes)” (75:2), and He also mentions Al nafs al mut’ma’inna, “O thou human being that hast attained to inner peace! (Mutmainna)”(87:27).
Allah was pointing out to the muslims Ilm al Nafs, the science of the self and He categorized three different types that would be common to all people and indirectly mentioned three types that are specific to the Prophets, Awiyah (saintly people) and the people of Jannah (heaven).
According to the majority of Muslim scholars the Nafs, can be change into seven states, the lowest one being an animalistic criminal state while the highest is the prophetic character.
Rasulullah (saws) said: “There shall always be 40 men in my ummah whose hearts will be similar to the heart of Ibrahim (as). Allah will remove difficulties from the people due to them. Their title is Abdal (substitute’s, because when one of them dies Allah substitutes another to take his place)”.
These stages can be considered part of the path of spiritual growth “Yet for all thou didst know, [O Muhammad,] he might perhaps have grown in purity”(80:3), from the lowest state of man to it’s perfections.
According to Allah in the Qur’an, the “soul” has two universal influences it can turn to which the nafs (self) is influenced by, the first is called “fujoor” and the second one is called “taqwa”;
Immorality (fujoor) is the lower reality that the “Nafs” (self) can experience and turn to, “Man has been created weak” (4:28)
Morality (taqwa) is the higher reality the “soul” can turn to, “And how He inspired it (Al-hama-ha, the soul) (to know) its Fujoor (Immorality) and its Ta’qwa (morality)” (91:8), the soul is pure and can’t be corrupted but it can be buried in darkness so it can’t perceive morality anymore, the nafs (self or ego) can bring a person down while the soul can lift him up again, this is similar to the struggle of Yin and Yang.
Yin and Yang in plain words is the evil that Allah placed in creation and the good that Allah placed in creation, this expression of Taqwa and Fujoor refers to what is already in creation and not what is in man, because Allah created evil and what is bad in the universe and gave the creatures he created capacity to be influenced by them as a test. They were created because it was part of Allah’s knowledge, His complete knowing of All things that can exist, everything that is good and everything that is evil is part of learning the knowledge that Allah knows.
The terminology that is used by the Chinese is different, incomplete and incorrect in places because they had an incomplete picture of creation.
When you can conceptualize what is in the universe entirely, you can then describe it more completely. In verse 91:8 Allah says He inspired the soul “to Know”, the verse means to know what is immoral for it and moral for it because Allah created man in the best of forms, he didn’t place immorality inside him.
Meaning good and evil are things external to us and the soul is inspired to identify the evil and good forces in creation, among all the things that Allah created whether objects or ideals and beliefs.
This is closer to the terminology of the Chinese, that Yin and Yang are forces (a term used to objectify all things in creation and see them in an abstract way), but they focus on the “science” of it all and say good and evil depend on each other. The dependence of good and evil on each other only resides in the fact Allah created them both and they aren’t going anywhere, you can not get rid of the evil present in creation, it’s actually more scientifically accurate to say evil is created from peoples actions because our actions mould what is in the universe into good or evil, otherwise it isn’t evil in and of itself. This relates to the human body because man is always in a state of loss (surah al Asr) unless he does specific things to protect himself so he is susceptible to weakness from himself and evil that comes from other peoples actions.
Adam (as) was created in Jannah (Heaven) a place entirely pure so man doesn’t actually need evil forces to exist because the highest state man can achieve and be constantly in, only reside in what is Good, this is seen in the example of the prophets (as), so the balance and harmony they perceive isn’t correct or a complete picture of the Universe.
“Verily, We have shown him the way (al ssabeela): either grateful or ungrateful”. (76:3) According to this verse, Man’s freewill is enabled to recognize immorality and morality in his Nafs (self) so man can free himself of evil.
Allah uses what we feel to guide us and inspire us to many things, an Artist to Art, a Chef to cook, an Architect to design but He has placed boundaries so we don’t hurt our self in these domains or fall into the perverse.
Because of mans corporeal (earthly) weakness which would impose a heavy burden upon his nafs (self) through his actions in life, Allah decreed and wanted to lighten the burdens on the self, He said in the Quran: “Allah wants to lighten your burdens: for man has been created weak.” (4:28) this is the ultimate wisdom behind Allah instructions in the Quran.
If man falls into to much desire it burns him out, degenerates his self and degrades him, most people maintain a balance but fall on the heavy side of these burdens on the self, and over time it impacts upon them until in their later years they have a nervous break down, the world has lost its meaning and the only freedom they can find is to stop caring about it.
If the balance of the self is maintained from the start, as Allah instructed us, then in our later years man would not suffer such things, those who pray as Allah said do not suffer anxiety.