The works of Ādi Śaṅkarācārya

Taittirīyopaniṣadbhāṣyam

Verse 15

देवपितृकार्याभ्या न प्रमदितव्यम् ।मातृदेवो भव ।पितृदेवो भव ।आ-चार्यदेवो भव ।अतिथिदेवो भव ।या-न्यनवद्यानि कर्माणि ।तानि सेवितव्या-नि ।नो इतराणि ।यान्यस्माक५ सुच-रितानि ।तानि त्वयोपास्यानि ॥ २ ॥

In plain words

Never neglect your duties to the gods and ancestors. Look upon your mother, your father, your teacher, and your guest as living presences of the divine. Follow only those actions that are pure and blameless, never any others. Emulate only the noble conduct of your teachers, and nothing else.

Close to the Sanskrit

Let there be no omission in duties to gods and ancestors. Treat your mother as a god, your father as a god, your teacher as a god, and your guest as a god. Whatever actions are blameless, those are to be performed, not others. Whatever good conduct is ours, that is to be revered by you.