KeU 4.8
तसै तपो दमः कर्मेति प्रतिष्ठा वेदाः सर्वाङ्गानि सत्यमायतनम्
The Upanishad is based on tapas (practice of the control of body, mind and senses), dama (subjugation of the senses), karma (right performance of prescribed actions). The Vedas are its limbs. Truth is its support.
Translated by Swami Paramananda
'The feet on which that Upanishad stands are penance, restraint, sacrifice; the Vedas are all its limbs, the True is its abode.
Translated by F. Max Müller