If we all are souls why do we all behave differently?

All Souls are the same! But each person is different. And the reason why each person is different is because of their karma. What are karmas? They are the effects of one’s past life causes.

Depending on the type of karma one has sown in their previous life, in one’s current life, the karmas unfold accordingly.
Each person’s mind, speech and actions work according to his or her past life’s karma and therefore every single person is uniquely different. If you notice, in every household there are so many different personalities and each one is very unique and different. There could be similarities, but it is very rare to find the same personality not only in the same household, but in the entire world, because everyone is dependent on the type of karma the individual has brought forth into this current life.

What is the connection between the Soul and Bodyr
Param Pujya Dada Bhagwan, the Enlightened being, explains that “There are six eternal elements in this world; they are everlasting. But when they revolve around each other, the phases of the element occur. And we are seeing these phases.”

Phases are always temporary, but the element is always permanent.
The Soul is one of the six eternal elements that revolve around each other. And the body, be it the body of a human, animal, insect or a celestial being, is a mere phase of the Soul and is temporary.

Just like the Sun, Moon and Earth revolve around each other and phases of the Moon is what we can see i.e., new-moon, full-moon etc— these phases of the Moon are temporary, but the Moon is not temporary. Likewise, Soul is not temporary, but human beings, animals, insects, etc. are the different phases of a Soul, which are temporary.

The Soul is an eternal element. Eternal means one that is neither created nor is ever destroyed. The Soul is made up of absolute knowledge. However, there are countless layers of deluding karma sitting over the Soul which obscures the knowledge of the Soul. Therefore, every living being, in its journey from complete ignorance to complete knowledge, has to go through infinite births, and in every birth, it assumes a different body. The Soul however always remains as it is!

The Journey of the Soul
The journey of the Soul begins from a stage where the Soul is totally covered by the deluding karma, and hence no knowledge or no vision is exposed at all. Later, when little covering breaks, the living being (the Soul with coverings over it) enters into the world as a one-sensed living being. And then, one develops from one-sensed to five-sensed living beings and evolves up to a human form (taking different forms of body in every birth and shedding karma all the while). Upon reaching human form, one’s mind, intellect, ego gets developed.

The Soul, which is one’s real Self, is not to be seen. Hence, one believes the body only to be himself, and thereby, one’s entire existence is based on the egoism of, ‘I am John (the name given to identify the body), I am doing (the actions done by the mind, speech and body), I am an uncle, I am a father (the relations of the body)’ and so on. Because of these false beliefs, one keeps binding karma. Based on the karma one has bound, in the next birth, he behaves accordingly, and simultaneously, owing to the false beliefs, once again binds new karma. Thus, one is stuck in the perpetual cycle of birth and death.

It is only in human form that we can escape from this cycle.
The Soul has always remained eternal and its inherent nature is knowledge and vision. Each and every living being has the awareness of ‘I am’, but the awareness of really ‘Who am I? and Who is the real doer?’ is lacking. This is the real reason for not realising our true Self - the Soul.
Only an enlightened being can destroy our ego and make us realise our true self. Once we realise, ‘I am a Pure Soul’ and the wrong belief of ‘I am the body’ is destroyed by the Enlightened being, then a firm inner conviction of ‘Who am I’ is established and the awareness of ‘I am a pure Soul’ begins.

To conclude: We all are Souls and every Soul is the same in nature. But based on the karma that lies on every individual Soul, the body of every living being is different and so is his nature. This is what makes each one of us behave differently.\

To know more: https://www.dadabhagwan.org/path-to-happiness/spiritual-science/what-is-a-soul/