Taittirīya Upaniṣad · 8

वेदमनूच्याचार्योऽन्तेवासिनमनुशास्ति । सत्यं वद । धर्मं चर । स्वाध्यायान्मा प्रमदः । आचार्याय प्रियं धनमाहृत्य प्रजातन्तुं मा व्यवच्छेत्सीः

vedamanūcyācāryo'ntevāsinam anuśāsti | satyaṃ vada | dharmaṃ cara | svādhyāyān mā pramadaḥ | ācāryāya priyaṃ dhanam āhṛtya prajātantuṃ mā vyavacchedhīḥ

Having taught the Veda, the teacher instructs the disciple: Speak the truth. Practice dharma. Do not neglect the study of the Scriptures. Having offered to the teacher agreeable wealth, do not cut the line of progeny.

This anuvāka presents the exhortation of the teacher to the disciple who has completed his study. It is a synthesis of dharma — the duties that lead to human flourishing and eventually to the knowledge of Brahman.

Satyaṃ vada — Speak the truth. More than simple honesty, this means expressing reality as it is perceived, without distortions of desire or fear. It is the foundation of all spiritual practice.

Dharmaṃ cara — Practice dharma. Dharma is what upholds — the actions that maintain cosmic and social order, and that purify the practitioner.

Svādhyāya — The continuous study of the Scriptures. It is not just reading, but recitation, memorization, and reflection upon the sacred texts.

The continuation of the family line (prajātantu) is mentioned as an ethical duty, recognizing that we are part of a continuity that transcends individual life.

For the modern yogi, these principles are applicable: truth in word and action, ethical practice, continuous study, and the recognition of our interconnection with all beings.