In the Vivekachudamani, Shankara says: this knowledge of the Self as the body - the wicked desire that I am the body - this is the root of birth and different sufferings.
Despite the body's limitations, imperfections, illnesses, deterioration, and death, deluded beings continually obsess with the finite form and thus habitually begin to mistake it for the Self. Instead of perceiving it as adhara - a container into which God pours a bit of his undying spirit - ignorant beings mistake the vessel for the content and suffer innumerable miseries. As Sri Shankaracharya states: consciousness remains untouched, ever pure; yet with the body and senses, the mind deludes consciousness and creates there the thought of me and mine. This delusion causes suffering.
The advise of Lord Buddha on attachment to the body is well known: he who has not any attachment to name and form, and does not grieve for what does not really exist, that one is wise beyond conception. Further he declared: O builder of the house, I have seen you. You shall not build the house again. All the rafters are broken, the ridge pole is sundered. Mind has arrived at dissolution, having attained the extinction of all cravings.
Speaking to his beloved disciple, Udhavva, Sri Krishna advises: living in the body which is under the sway of past actions, the deluded one becomes bound due to identification with it.