Tzava'at Harivash 42

The concentration on every word ought to be to the point that the word is “illuminated and shines” (see below, sect. 75). Deveikut to God is by means of attaching one’s thought and inwardness to the spiritual core of the letters of Torah and prayer-the spiritual core of the light of the En Soph that is in the letters, an “attachment of spirit to spirit.” (Keter Shem Tov, sect. 44 and 94) Thus when saying a word, you prolong it extensively and do not want to let go of it (below, sect. 70). There is then an intense communion to the point of “my soul yearns, it expires, for the courtyards of God” (Psalms 84:3). Thus it may be natural to die (kelot hanefesh-expiration of the soul from its pining for God) after reciting but two or three words from the prayer.

Prayer with great deveikut may lead to a sense of self-satisfaction or other ulterior thoughts. The Baal Shem Tov thus cautions to beware, that the prayer be followed by a profound sense of humility. (See Darkei Tzedek, I:no. 5.) Cf. above, sect. 12.