PRAŚNA UPANISHAD · 5.6

तिस्रो मात्रा मृत्युमत्यः प्रयुक्ता
अन्योन्यसक्ताः अनविप्रयुक्ताः ।
क्रियासु बाह्याभ्यन्तरमध्यमासु
सम्यक् प्रयुक्तासु न कम्पते ज्ञः ॥ ५.६॥

tisro mātrā mṛtyumatyaḥ prayuktā
anyonyasaktāḥ anaviprayuktāḥ ।
kriyāsu bāhyābhyantaramadhyamāsu
samyak prayuktāsu na kampate jñaḥ ॥ 5.6॥

“‘Children of death are the letters when they are used as three, the embracing and the inseparable letters; but the wise man is not shaken; for there are three kinds of works, outward deed and inward action and another which is blended of the two, and all these he doeth rightly without fear and without trembling.

Sri Aurobindo · CWSA 18, p. 189