In the current state of physical deterioration, after the sin of Adam, the soul does not perform its intended function, which is to purify the body. This is why it is necessary for there to be death, followed by the revival of the dead. This revival will find us in new bodies that are not tainted by Adam's sin, and are therefore capable of being raised by the soul to true spiritual level. Derech Hashem 1:3 9-10