Śarīraṁ haviḥ शरीरं हविः॥ (sūtra II.8)
Śarīraṁ - body; haviḥ - oblation.
In this sūtra, body means the body of a yogi whose qualities have been discussed in the previous aphorisms. Yogi is a person who is able to unite his individual consciousness with universal consciousness. A person totally devoid of ego is a yogi. All human beings have three types of bodies, gross, subtle and subtlest. Gross is the physical body, subtle body can be explained as the body conceived in the arena of mind and the subtlest of the three is the soul within. This can be compared to a tyre (tier) of an automobile. The exterior part made of rubber is the gross body. The inner tube that holds air within is the subtler body and the air that is invisible, but is the most important of the three, on which not only the other two depend upon, but also the automobile itself and its passengers also depend for mobility is the subtlest of all. There is no use of an automobile without the subtlest air. Same is the case with the human body and the subtlest of human body is the soul. It also signifies that the subtlest has more potency than the gross. God is the subtlest of all, hence He is omnipotent.
As far as the human body is concerned, the other two bodies form as coverings for the inner and invisible soul. This aphorism says that I consciousness is to be removed from all the three bodies. This becomes possible only through thought process and continuous affirmation saying that I am That or ahaṁ brahmāsmi. One cannot become Brahman just by verbal affirmation. In the same way no mantra will be effective, unless effulgence of mantra is realised through thought process.
Ego is reflected through I consciousness that percolates into all three types of bodies and if this percolation is allowed to happen for long, destroying this I consciousness becomes difficult. In the early stage of spiritual path, if I consciousness in all the three levels of a body are offered as oblations into the fire of God consciousness or Śiva consciousness, ego is burnt into ashes not to rear again. It is not just enough to offer these oblations but repeatedly affirm that evils of ego have been reduced to ashes and what exists now is that of Śiva or belong to Śiva. Such a transformed yogi will not repeat namaśivāya, the great mantra of Śiva, but he will turn into Śiva himself and affirm confidently śivohaṁ, meaning I am Śiva.
Kṛṣṇa says in Bhagavad Gīta (IV.25 - 27), “Some yogis offer oblations to gods alone, while others offer oblations as sacrifice by the Self in the fire of Brahman. Yet others offer senses as oblations in the fires of restraint. Some others sacrifice all the functions of the senses in the fire of yoga by self-restraint, kindled by knowledge.”