अविद्यया मृत्युं तीर्त्वा विद्ययाऽमृतमश्नुते
avidyayā mṛtyuṁ tīrtvā vidyayā amṛtam aśnute
Through Avidyā, ignorance, you cross beyond mortality, beyond death, beyond change; through Vidyā, knowledge, you taste immortality.
Īśā Upaniṣad 11
The Self is always the Self; it is never non-Self; but somehow it became identified with the body and with the whole objective field of life. So the ‘I’ got mixed up with ‘mine’; and when the ‘I’ awakens fully to its own original identity, then is the taste of immortality.
The practice is just for this—to awaken to one’s own immortal reality. And practice means we go beyond that which we have been identified all the time—we transcend that, and transcend, and transcend, and transcend.... With time the taste of transcendental consciousness begins to be a little more lasting, more lasting, more lasting, and gradually the long identification with the boundaries of the body and the surroundings begins to dissolve. Those impressions begin to melt.
So this practice, or Sādhanā, is just for the sake of transcending change. Through change you transcend change. That is why it says, through ignorance you cross beyond the field of change—through ignorance. Because enlightenment is the reality; ignorance is a mirage. You have the glasses on the eyes, but you are searching—where are the glasses? You are the Self, but you are searching—where is the Self, where is the Self? So the whole search is a kind of fraud, which is just Avidyā. The reality is eternity, immortality; so you taste immortality by virtue of being immortality. But to be immortal, you have first to cross beyond the boundaries of change. Through change you transcend change; through knowledge, that awakening, you taste immortality.
Maharishi Mahesh Yogi, 6 December 1964, History of Thirty Years around the World, p.574.