"Only heart to heart can speak the bliss of mystic knowers; No messenger can tell it and no missive bear it."

... "The pen steppeth not into this region, the ink leaveth only a blot. In these planes, the nightingale of the heart hath other songs and secrets, which make the heart to stir and the soul to clamor, but this mystery of inner meaning may be whispered only from heart to heart, confided only from breast to breast.

Only heart to heart can speak the bliss of mystic knowers;
No messenger can tell it and no missive bear it. 2

I am silent from weakness on many a matter,
For my words could not reckon them and my speech would fall short. 3

O friend, till thou enter the garden of such mysteries, thou shalt never set lip to the undying wine of this Valley. " ...

-Bahá'u'lláh, The Seven Valleys And the Four Valleys, p. 30

2.	Háfiz: Shamsu’d-Dín Muḥammad, of Shíráz, died ca. 1389 A.D. One of the greatest of Persian poets.
3.	Arabian poem.