Vidyāśarīrasattā mantrarahasyam विद्याशरीरसत्ता मन्त्ररहस्यम् (sūtra II.3)
Vidyā – the highest knowledge that is required to feel the oneness with the Ultimate Reality, Śiva; śarīra – bodily form and here it means core knowledge or vidyā referred above; sattā – excellence; mantra – mantra (not the routine mantra-s, but the supreme I consciousness); rahasyam – secret.
This sūtra means that the supreme knowledge of oneness with Ultimate Reality is revealed through the inherent essence of I consciousness that is present in empirical individual. Mantra here means the essence of non-dualism or oneness with Supreme consciousness. Realization of oneness of macrocosms with microcosms is dealt with in this sūtra. Such realization is called mantrarahasyam.
In the last few sūtra-s, word mantra has been frequently used. As discussed earlier, mantra here means principle of “I am That”. Affirming “I am That” is the essence of all the mantra-s. If an aspirant fails to make this affirmation, he cannot make significant spiritual progress. It is said that mantra-s consisting of alphabets are made only to establish a firm link with the concerned deity. Here mantra merely helps to concentrate on a gross form. Oneness with the concerned deity can happen only through thought process. Realization can happen only at the subtle level and not at the gross level. Subtle level is the domain of mind and gross level is the domain of senses. Mere chanting of mantra-s without understanding the underlying factor of “I am That”, the essence of Self-realization, does not carry the aspirant anywhere near the logical goal of bliss ultimate realization. This aspect of knowing is called secret. The self affirmation described above is the secret.
It has been repeatedly stated that the thought of dualism is a deterrent factor in spiritual attainment. Non-dualism is the foundational principle of spirituality. Non-dualism alone corroborates the omnipresent nature of the Lord. Merging of empirical consciousness with cosmic consciousness (cosmic because of omnipresent nature) is the secret of attaining spiritual consecration. Supreme knowledge refers to the understanding the subtle nature of Ultimate Reality. A scholar is different from a yogi. A scholar’s knowledge is gross in nature, but a yogi’s knowledge is subtle in nature. Gross can be realised through senses and subtle can be realised only through aligning individual consciousness with Supreme consciousness. Till such time the perfect alignment sets in through practice, right kind of spiritual progression cannot be attained