नैमिषोपाख्यानं नाम तृतीयोऽध्यायः
Naimisharanya episode Chapter 3
Brahma said (to the sages)
यतो वाचो निवर्तन्ते अप्राप्य मनसा सह |
आनन्दं यस्य वै विद्वान्न बिभेति कुतश्चन || 1 ||
That without grasping which speech turns back along with the mind, whose joy,
a knowledgeable person does not fear for any reason.
The first half of this shloka also appears in Taittiriya Upanishad, Chapter 2, shloka 9.