Passage
Taittiriya Upanisad TaittU_3,10.1
san taittiriya
na kaṃcana vasatau pratyācakṣīta / tad vratam / tasmādyayā kayā ca vidhayā bahvannaṃ prāpnuyāt / arādhyasmā annam ityācakṣate / etadvai mukhato 'nnaṃ rāddham / mukhato 'smā annaṃ rādhyate / etadvai madhyato 'nnaṃ rāddham / madhyato 'smā annaṃ rādhyate / etadvai antato 'nnaṃ rāddham / antato 'smā annaṃ rādhyate