MUṆḌAKA UPANISHAD · 2.2.4

प्रणवो धनुः शरो ह्यात्मा ब्रह्म तल्लक्ष्यमुच्यते ।
अप्रमत्तेन वेद्धव्यं शरवत्तन्मयो भवेत् ॥ ४॥

praṇavo dhanuḥ śaro hyātmā brahma tallakṣyamucyate ।
apramattena veddhavyaṃ śaravattanmayo bhavet ॥ 4॥

OM is the bow and the soul is the arrow, and That, even the Brahman, is spoken of as the target. That must be pierced with an unfaltering aim; one must be absorbed into That as an arrow is lost in its target.