Dought & clear, - What do the words hulool (incarnation) and ittihaad (union with the divine) mean?

When I read books about belief (‘aqeedah), I often come across refutations of those who believe in ittihaad (union with the divine), refutations of those who believe in wahdat al-wujood (“unity of being”), and so on. What is meant by hulool (incarnation) and ittihaad (union with the divine)?
Praise be to Allah.
Hulool (incarnation) and ittihaad (union with the divine) – which includes the term wahdat al-wujood (“unity of being”):
These two terms are often mentioned in books on beliefs (‘aqeedah). They are esoteric and Sufi terms, and these concepts are also frequently mentioned in the books of false religions such as those of the Brahmins, Buddhists and others.
1. Hulool (incarnation)
(a)
What this word means in general terminology is when one of two things is absorbed into or incarnated into another.
This is complete mixing.
Al-Jarjaani (may Allah have mercy on him) said:
Complete hulool is the union of two bodies in such a way that pointing to one is also pointing to the other, such as the juice in an orange.
Incomplete hulool is when one of the two entities acts as a vessel containing the other, such as water in a jug.
At-Ta‘reefaat, p. 92.
This is what is meant by hulool: affirmation of two entities, one of which is present in the other.
What is meant by this word as used by Sufis and others is the incarnation or presence of Allah – may He be glorified and exalted – in His creation or in some of His creation.
(b)
Types of hulool
Hulool may be divided into two types:
i. General hulool, which is the belief that Allah, may He be exalted, is present in all things.
But this hulool is similar to the idea of the incarnation of the divine (i.e., the Creator God) in the human (i.e., the created being), whilst affirming that the two entities are distinct and separate; in other words, He is not unified with the one in whom He is present, rather He is everywhere yet separate. Thus this is confirmation of two separate entities.
This is the view of the Jahamis and their ilk.
ii. Specific hulool, which is the belief that Allah – may He be glorified and exalted – is present in some of His creation, whilst believing that there is a Creator and a created being.
This is like the belief of some of the Christian sects, that divinity – meaning Allah, may He be glorified and exalted – is incarnated in humanity – meaning ‘Eesa (Jesus, peace be upon him) – and that ‘Eesa (peace be upon him) has two natures: the divine nature when he was speaking words of revelation, and a human nature when he was crucified (according to their belief).
This is also similar to the belief of some of the extreme Raafidis, such as the Nusayris, who believe that Allah – may He be glorified and exalted – was incarnated in ‘Ali ibn Abi Taalib, who was God (according to their belief); thus divinity was incarnated in him. This is one of their basic beliefs.
2. Ittihaad (union with the divine)
(a)
What is meant by ittihaad is that two things are one thing.
Al-Jarjaani (may Allah have mercy on him) said:
Ittihaad means the mixing of two things until they become one thing.
At-Ta‘reefaat, p. 9
(b)
what is meant, according to those who believe in this notion, is that Allah – may He be glorified and exalted – becomes one with His creation or with some of His creation, in the sense that all created beings or some of them are the exact essence of Allah, may He be exalted.
(c)
Types of ittihaad:
i. Ittihaad in a general sense – which is also called wahdat al-wujood (“unity of being”). This is the belief that everything that exists is God Himself. In other words, the Creator is one with all of His creation. This is the meaning of wahdat al-wujood; those who believe in it are called al-ittihaadiyyah or ahl wahdat al-wujood, such as Ibn al-Faarid, Ibn ‘Arabi and others.
ii. Ittihaad in a specific sense, which is the belief that Allah, may He be glorified and exalted, became one with some created beings but not others.
Those who believe in this exclude from it the idea of His being one with filthy and abhorrent things; they say that He became one with the Prophets, the righteous, the philosophers or others, and thus they became the exact essence of Allah, may He be glorified and exalted.
This is like the view of some Christian sects who believe that divinity became one with humanity, and they became one thing. This is unlike those who believe in incarnation, who believe that he (i.e., Christ) has two natures, divine and human.
Those who believe in ittihaad say one nature, and those who believe in hulool say two.
(d)
The difference between hulool and ittihaad
The difference between them may be summed up as follows:
i. Hulool affirms two entities, unlike ittihaad which affirms one entity.
ii. Hulool accepts that they are separable, whereas ittihaad does not accept that.
(e)
Examples that explain the difference between hulool and ittihaad:
There are many such examples, including the following:
If you put sugar into water without stirring it, this is hulool, because they are still two separate entities. But if you stir it until it is absorbed by the water, then they become one, because they cannot be separated again.
But if you put something different into the water, such as pebbles, then this is called hulool, not ittihaad, because the pebbles are one thing and the water is something else, and they can be separated.
(f)
Ruling on which of these two beliefs is worse
There is no doubt that believing in hulool or ittihaad is one of the greatest kinds of disbelief and heresy – Allah forbid.
But ittihaad is worse than hulool, because it is belief in one essence, unlike hulool. Moreover, the belief that He is one with everything is worse than the belief that He is one with some of His creation.
To sum up, belief in hulool and ittihaad is obviously false. Islam came to erase it from people’s minds, because it is a belief that is taken from the teachings, philosophies and idolatry of the Hindus, Greeks, Jews, Christians and others, so it is based on fabrications and myths.
Taken fromMustalahaat fi Kutub al-‘Aqaa’idby Shaykh Muhammad ibn Ibraaheem al-Hamad, p. 42-47
And Allah knows best.