He who thinks he does not know It, knows It. He who thinks he knows It, does not know It. The true knowers think they can never know It (because of Its infinitude), while the ignorant think they know It.
“Those who know do not speak; those who speak do not know.”
[N.B.Translation of the original mantras of the Upanishadis given in the italics.]
This Upanishad derives its name from the opening word of the text, Kena-ishitam, "by whom directed." It is also known as the Talavakara-Upanishad because of its place as a chapter in the Talavakara-Brahmana of the Sama-Veda.
It has four sections, the first two in verse form and the other two in prose. The verse form deals with the Supreme Unqualified Brahman, the absolute principle underlying the phenomenal world and the prose form deals with the Supreme as God, Isvara. The knowledge of the Absolute is possible only for those who are able to withdraw their thoughts from the worldly objects and concentrate on the ultimate fact of the universe. The knowledge of Isvara puts him on the path way to deliverance in course of time. Such a worshipping soul gradually acquires the higher wisdom which results in the consciousness of identity with the Supreme.
Among the Upanishads it is one of the most analytical and metaphysical, its purpose being to lead the mind from the gross to the subtle, from the effect to the cause. By a series of profound questions and answers, it seeks to locate the source of man's being; and to expand his self-consciousness until it has become identical with God-Consciousness, Brahman.
“May my limbs, speech, Prana (life-force), sight, hearing, strength and all my senses, gain in vigor? All is the Brahman (Supreme Lord) of the Upanishads. May I never deny the Brahman? May the Brahman never deny me? May there be no denial of the Brahman. May there be no spurning by the Brahman. May all the virtues declared in the sacred Upanishads be manifest in me, who am devoted to the Atman (Higher Self). May they be manifest in me? OM! PEACE! PEACE! PEACE!”