Question: Given the rules of my world as explained below, how can I justify "The First Iron Law of Necromancy?"

A living person can't simply raise the dead from their slumber, only somebody who is dead, themselves, can do it. This fact is reflected in "the first iron law of necromancy," which is commonly known by all practitioners of magic. I would like the reason for this law to play an important part in my story, so I need to develop it as a rule of my world.

The Rules Thus Far

In necromancy, the word "dead" has a more precise meaning than in everyday speech.

• A living person (regardless of species) has both a body and soul. Compare this to, for example, plants, which have a living biological process, but do not have souls. In necromancy, a plant cannot be dead because, not having a soul, it was never "alive" to begin with.

• A person is "alive" when their soul is not in the world of the dead, not even partly. Their soul is entirely in the world of the living.

• A person is truly dead when their soul has entirely entered the world of the dead. Once a soul has entered that world it cannot entirely leave it.

• An undead person is one whose soul has been stretched between the two worlds, being neither completely alive nor completely dead.

Raising the dead means to stretch souls of the dead from the world of the dead partly into the world of the living, i.e. make them undead.

Because it is impossible to escape the world of the dead it is impossible to be fully resurrected. This is "The Second Iron Law of Necromancy," true resurrection (bringing a soul entirely into the world of the living) is impossible.

Raising the dead has a price: In order to become a necromancer you need to perform a ritual that will kill you, but at the same time will preserve some of your connections with the world of the living. You become, in my world, a lich. The ritual must be executed flawlessly or the wanna-be-necromancer will be just plain dead.

Many people would like to raise the dead without performing the ritual and paying the price. But alas, this is impossible.

I need help developing the rule of my world that makes avoiding the ritual impossible.

Question: Given the rules of my world as explained below, how can I justify "The First Iron Law of Necromancy?"

A living person can't simply raise the dead from their slumber, only somebody who is dead, themselves, can do it. This fact is reflected in "the first iron law of necromancy," which is commonly known by all practitioners of all kinds of magic. I would like to see possible reason for this law.

The Rules Thus Far

In necromancy, the word "dead" has a more precise meaning than in everyday speech.

• A living person (regardless of species) has a soul. Compare this to, for example, plants, which have a living biological process, but do not have souls. In necromancy, a plant cannot be dead because, not having a soul, it was never "alive" to begin with.

• A person is "alive" when their soul is not in the world of the dead, not even partly. Their soul is entirely in the world of the living.

• A person is dead when their soul is either entirely or partly in the world of the dead. Once a soul has entered that world it cannot entirely leave it.

• An undead person is one whose soul has been stretched between the two worlds. They are not partly alive and partly dead, they are 100% dead, as if you have a soul you can be either entirely alive or entirely dead, with no gradation between them.

Raising the dead means to stretch souls of the dead from the world of the dead partly into the world of the living, i.e. make them undead.

Because it is impossible to escape the world of the dead it is impossible to be fully resurrected. This is "The Second Iron Law of Necromancy," true resurrection (bringing a soul entirely into the world of the living) is impossible.

To get ability to raise the dead you need to pay a price: In order to become a necromancer you need to perform a ritual that will kill you, but at the same time will preserve some of your connections with the world of the living. You become, in my world, a lich. The ritual must be executed flawlessly or the wanna-be-necromancer will be just plain dead.

Many people would like to raise the dead without performing the ritual and paying the price. But alas, this is impossible.

You can help me to explain why it's impossible to break the First Iron Law of Necromancy and thus avoid need to perform the ritual.

UPDATE: the question was rewritten in order to get it reopened

The living (of any species, not limited to humans) just can't raise the dead from their slumber, only somebody dead can. It's called "the first iron law of necromancy" and so basic, that even magicians who practice other forms of magic know this law. This being said, word "dead" in the law is used in more precise meaning than in everyday speech, namely to describe somebody whose soul entered the world of the dead. Once a soul entered said world it cannot leave it. As for living beings, in necromancy they are defined to be beings whose souls are not the world of the dead, even partly. And undead beings are defined as a subset of the dead, namely dead ones whose souls have been stretched between the world of the living and the world of the dead. To "raise the dead" also means to stretch souls of the dead from the world of the dead to the world of the living, i.e. make them undead. Some beings, like plants, have no soul and thus considered neither dead nor alive nor undead.

From definitions and impossiblity to escape the world of the dead follows so-called the second iron law of necromancy, also so basic that is widely known by magicians of all fields of magic: you cannot make the dead alive again, i.e. true resurrection is impossible. There were mages who claimed that they broke the second iron law of necromancy with very advanced holy magic, but each time it turned out that it was a sham and said mages really were just necromancers in white robes.

In order to become a necromancer you need to perform a ritual that will kill you, but at the same time will preserve some of your connections with the world of the living, so you will be able to raise yourself from the dead and thus become the lich. Such necromantical "pulling yourself by your boot straps" needs to be executed flawlessly, otherwise even a small mistake can result in a wanna-be-necromancer becoming just plain dead, instead of a lich. You also can't rely on other lich raise you from the dead, as in this case you will lose your magical powers and will become a slave of said lich. Many people would like to be able to raise the dead without performing the ritual on themselves. But alas, this is impossible because ...

Question: Given the rules of my world as explained below, how can I justify "The First Iron Law of Necromancy?"

A living person can't simply raise the dead from their slumber, only somebody who is dead, themselves, can do it. This fact is reflected in "the first iron law of necromancy," which is commonly known by all practitioners of magic. I would like the reason for this law to play an important part in my story, so I need to develop it as a rule of my world.

The Rules Thus Far

In necromancy, the word "dead" has a more precise meaning than in everyday speech.

• A living person (regardless of species) has both a body and soul. Compare this to, for example, plants, which have a living biological process, but do not have souls. In necromancy, a plant cannot be dead because, not having a soul, it was never "alive" to begin with.

• A person is "alive" when their soul is not in the world of the dead, not even partly. Their soul is entirely in the world of the living.

• A person is truly dead when their soul has entirely entered the world of the dead. Once a soul has entered that world it cannot entirely leave it.

• An undead person is one whose soul has been stretched between the two worlds, being neither completely alive nor completely dead.

Raising the dead means to stretch souls of the dead from the world of the dead partly into the world of the living, i.e. make them undead.

Because it is impossible to escape the world of the dead it is impossible to be fully resurrected. This is "The Second Iron Law of Necromancy," true resurrection (bringing a soul entirely into the world of the living) is impossible.

Raising the dead has a price: In order to become a necromancer you need to perform a ritual that will kill you, but at the same time will preserve some of your connections with the world of the living. You become, in my world, a lich. The ritual must be executed flawlessly or the wanna-be-necromancer will be just plain dead. 

Many people would like to raise the dead without performing the ritual and paying the price. But alas, this is impossible.

I need help developing the rule of my world that makes avoiding the ritual impossible.

The living just can't raise the dead from their slumber, only other dead ones can. Like, in order to become a necromancer you need to perform a ritual that will kill you, but at the same time will preserve some of your connections with the world of the living, so you will be able to raise yourself from the dead. Such necromantical "pulling yourself by your boot straps" needs to be executed flawlessly, otherwise even a small mistake can result in a wanna-be-necromancer becoming just plain dead, instead of a lich. For this reason many people would like to be able to raise the dead without performing the ritual on themselves. But alas, this is impossible because ...

UPDATE: the question was rewritten in order to get it reopened

The living (of any species, not limited to humans) just can't raise the dead from their slumber, only somebody dead can. It's called "the first iron law of necromancy" and so basic, that even magicians who practice other forms of magic know this law. This being said, word "dead" in the law is used in more precise meaning than in everyday speech, namely to describe somebody whose soul entered the world of the dead. Once a soul entered said world it cannot leave it. As for living beings, in necromancy they are defined to be beings whose souls are not the world of the dead, even partly. And undead beings are defined as a subset of the dead, namely dead ones whose souls have been stretched between the world of the living and the world of the dead. To "raise the dead" also means to stretch souls of the dead from the world of the dead to the world of the living, i.e. make them undead. Some beings, like plants, have no soul and thus considered neither dead nor alive nor undead.

From definitions and impossiblity to escape the world of the dead follows so-called the second iron law of necromancy, also so basic that is widely known by magicians of all fields of magic: you cannot make the dead alive again, i.e. true resurrection is impossible. There were mages who claimed that they broke the second iron law of necromancy with very advanced holy magic, but each time it turned out that it was a sham and said mages really were just necromancers in white robes.

In order to become a necromancer you need to perform a ritual that will kill you, but at the same time will preserve some of your connections with the world of the living, so you will be able to raise yourself from the dead and thus become the lich. Such necromantical "pulling yourself by your boot straps" needs to be executed flawlessly, otherwise even a small mistake can result in a wanna-be-necromancer becoming just plain dead, instead of a lich. You also can't rely on other lich raise you from the dead, as in this case you will lose your magical powers and will become a slave of said lich. Many people would like to be able to raise the dead without performing the ritual on themselves. But alas, this is impossible because ...