The Maitrayaniya or Maitri Upanishad belongs to the Maitri or Maitrayaniya branch of the Krsna Yajurveda, though some texts assign it to the Samaveda
"Let a man strive to purify his thoughts. What a man thinketh, that is he this is the eternal mystery. Dwelling within himself with thoughts serene, he will obtain imperishable happiness."
