Soul is a part of G-d

 Ramchal (Daas Tevunos 24) The soul is a part of G-d. Its desire is to return and cleave to its source and to grasp it, as is the nature of everything of heavenly source to desire it return to the heights of heaven, and it does not achieve its rest until it achieves this.  

Tanya |(01 chapter 1:15) Rabbi Chaim Vital wrote in Shaar HaKedushah and in Etz Chaim, Portal 50, ch. 2 that in every Jew, whether righteous or wicked, are two souls, as it is written, “The souls which I have made,” alluding to two souls. There is one soul which originates in the kelipah and sitra achara, and which is clothed in the blood of a human being, giving life to the body, as is written, “For the life of the flesh is in the blood.” From it stem all the evil characteristics deriving from the four evil elements which are contained in it. These are: anger and pride, which emanate from the element of Fire, the nature of which is to rise upward; the appetite for pleasures—from the element of Water, for water makes to grow all kinds of enjoyment; frivolity and scoffing, boasting and idle talk from the element of Air; and sloth and melancholy—from the element of Earth.

Tanya |(01 chapter 2:01) The second soul of a Jew is truly a part of G–d above, as it is written, “He breathed into his nostrils a soul of life,” and “You have breathed it [the soul] into me.” And it is written in the Zohar, “He who blows, blows from within him,” that is to say, from his inwardness and his innermost, for it is something of his internal and innermost vitality that man emits through exhaling with force.

Tanya (01 chapter 19) “The candle of G–d is the soul  of man.” What it means is that the souls of Jews, who are called “man,” are, by way of illustration, like the flame of the candle, whose nature it is always to flicker upward, for the flame of the fire intrinsically seeks to be parted from the wick in order to unite with its source above in the universal element of fire which is in the sublunar sphere, as is explained in Etz Chaim. And although it would thereby be extinguished and emit no light at all below, and even above, in its source, its light would be nullified, nevertheless this is what it seeks in accordance with its nature. In like manner does the neshamah of man, including the quality of ruach and nefesh, naturally desire and yearn to separate itself and depart from the body in order to unite with its origin and source in G–d, the Fountainhead of life, blessed is He, though thereby it would become null and void, completely losing its entity therein, with nothing remaining of its former essence and being. Nevertheless, this is its will and desire by its nature. “Nature” is an applied term for anything that is not in the realm of reason and comprehension.