Upanishad introduction by Jacques Bonnet, 1984.

OM PURNAMADAH PURNAMIDAM
PURNATH PURNAMUDACHYATE
PURNASYA PURNAMADAYA
PURNAMEVA VASISHYATE

The evangelic texts distinguish " those who know " from " those who do not know ". It is the distinction that the Hindu doctrines, those of the Upanishad and Vedanta, make between vidyă, knowledge and avidyă, misunderstanding. And it turns out that this distinction applies to what is even the object of the words of Jesus, the relation of man to God.
"Those who moving in avidyă, imagine wise men and scholars roam on all sides, turn in circle distraught as blind persons led by a blind person." Verse repeated in three Upanishad: Maitry Upanishad 7.9.1. Mundaka Upanishad 1.2.8. Katha Upanishad II, 5. Verse completed by: "Vidyă and avidyă, who knows both, having crossed the death due to the avidyă reaches the non-death due to the vidyă ". (Maitry Upanishad 7.9 and Isha Upanishad 14).
This characteristic of wandering is opposed to the attitude of the one who knows his road: "where from" to "where" (in Hebrew Meain ¨, Leain ¨, An). Avidyă, the misunderstanding of what we really are is also Măyă, illusion. This illusion results from an overprinting ( upădhi ), an addition which we impose on reality.

p.158-159, "Midrash of Saint John's gospel", Jacques BONNET, 1984, 4th ed. ISBN 2-9500315-I-X.