The Kena Upanishad chapter 1, verse 2 says: "Since He is the Ear of the ear, the Mind of the mind, the Speech of speech, the Life of life, and the Eye of the eye, the intelligent man after giving up self-identification with the senses and renouncing this world, becomes immortal."
Therefore, Brahman, Truth, cannot be perceived by the 5 sense organs, 12 pairs of cranial nerves, and 24 gross elements or by speaking highly of it. Nor can Brahman be reached by ceremonies or philosophical speculation, suggestion or imagination. Wisdom can be perceived by the atom only. The truly intelligent person is one who sincerely desires self-realization and meditates to achieve this supreme goal.
The Kena Upanishad also says 2:4 says: "Brahman is really known when it is known as the Self of each state of consciousness, because thereby one gets immortality. Knowing that everything is God, finding the Self within, and seeing that God is the doer lead to immortality - oneness with Brahman. It leads away from your human stage, your negatives. It leads to eternal peace, joy, bliss, mercy, kindness, lovingness, sweetness, purity and divinity.