Devibhagavatapurana 7.36.5

7.36.5

dhanurgṛhītvaupaniṣadaṃ mahāstraṃ śaraṃ hyupāsāniśitaṃ sandhayīta |
āyamya tadbhāvagatena cetasā lakṣyaṃ tadevākṣaraṃ saumya viddhi ||

Take hold of the Mystic Name as the bow, and know that the Brahman is the aim to be hit. Put on this the great weapon (Om), the arrow (of the mind) sharpened by meditation. Withdraw thyself from all objects, and with the mind absorbed in the idea of Brahman, hit the aim; for know, O Saumya! That Imperishable alone to be the Mark. The Great name"Om" is the bow, the mind is the arrow, and the Brahman is said to be the mark. It is to be hit by a man whose thoughts are concentrated, for then he enters the target.
Note. -- Thus S'ravana, Manana, and Dhyâna of Brahman have been taught. This is the method of Brahma-upâsanâ.