The soul and the body are not identical.
Were the soul to so dominate the human being that life would express only the soul, then the human being would disappear as soon as the soul left.
Which, incidentally, is connected with the matter of sin and repentance.
For if a person sinned in such a way that his punishment is to be cut off, then his soul would be consumed and the person would cease to exist.
The whole point of repentance is that a human being does, somehow, continue to exist, at least certain remnants do, in order to be able to make amends.
In other words, human beings have, in this sense, a double life.
There is the life of the body and the life of the soul.
And it is this that makes for problems in the spiritual life, because the body has its own desires.
It does not merely express the desires of the soul.
For instance: I decide to put my hand into the fire and I can observe how the body protests.
–Rabbi Adin Steinsaltz