Na represents Siva and his elusive grace, Ma is the world, Śi stands for Śiva, Va represents the identifiable grace in God, and Ya is the soul: each of these aspects represent your true self in the present, past and future.
Chanting Om Namaḥ Śivaya helps one to detach from the material world and to focus more on one's true self- the self that is one with and the same as God. Admitting that the material world causes us to be blind is the first step to being able to see our true nature and selves- filled with light, love and grace.
It is a five-syllable mantra (Om is not included in the count), and each syllable represents the five elements of earth, water, fire, air, and space. Each making us aware of how we became manifest, and in turn reminding us of the supreme source of energy from which those elements became manifest themselves.