CHĀNDOGYA UPANISHAD · 1.3.9

यस्याम् ऋचि ताम् ऋचं, यद् आर्षेयं तम् ऋषिं, यां देवताम् अभिष्टोष्यन् स्यात् तां देवताम् उपधावेत् ॥

yasyām ṛci tām ṛcaṃ, yad ārṣeyaṃ tam ṛṣiṃ, yāṃ devatām abhiṣṭoṣyan syāt tāṃ devatām upadhāvet ॥

Let him quickly reflect on the Rik in which that Sâman occurs; on the Rishi (poet) by whom it was seen or composed; on the Devatâ (object) which he is going to praise;