Śarīre saṁhāraḥ kalānām शरीरे संहारः कलानाम्॥ (sūtra III.4) 

Śarīre – body (gross, subtle and casual); saṁhāraḥ - destruction; kalānām – principles that have been discussed in the previous aphorism.

This sūtra elucidates the means to get rid of the bondage caused by mind, as discussed in the previous sūtra. The ultimate aim of any spiritual aspirant to merge into Śiva, who can be reached only after transcending Kalā, Suddhavidyā, Īśvara, Sadāśiva and Śaktī. When Śaktī is satisfied, She takes the aspirant to Śiva. The said five principles are in the form coverings around Śiva, who is the central point or bindu. If one is desirous of reaching Śiva, he has to cross over these five coverings and during this transgression, the mind of the aspirant undergoes refinement. One cannot move on to the next stage, unless his mind undergoes significant purification process.

Body refers to all the three types of bodies. Gross body is the physical body where all the five great elements are embedded. Subtle body consists of five tanmātra-s (śabda, sparśa, rūpa, rasa and gandha or sound, touch, form, taste and smell) in conjunction with antaḥkaraṇa. Antaḥkaraṇa is very subtle in nature and consists of mind, intellect and ego. The subtlest amongst the three types of bodies is the casual body and consists of prāṇa, the subtlest and important of all. The mind has to transcend all the three types of body to realise Śiva. Saṁhāraḥ in this sūtra means annihilation of gross body into subtle body; and subtle body into casual body and ultimately leaving nothing to be annihilated. This process can be compared to the three stages of consciousness – awake, dream and deep sleep. When one enters the stage of deep sleep, each stage is dissolved into the next higher. 

This sūtra says that this process of stage by stage annihilation should be contemplated in the arena of mind where ultimately nothing is left for contemplation and dissolution. He now enters the state of void and this is the point where Śiva is realised.