ओमिति ब्रह्म ।ओमितीद५ सर्वम् ।ओमित्येतदनुकृतिर्ह स्म वा अप्यो श्राव-येत्याश्रावयन्ति ।ओमिति सामानि गा-यन्ति ।ओ५ शोमिति शस्त्राणि श५स-न्ति ।ओमित्यध्वर्युः प्रतिगरं प्रतिगृणा-ति ।ओमिति ब्रह्मा प्रसौति ।ओमित्य-ग्निहोत्रमनुजानाति ।ओमिति ब्राह्मणप्रवक्ष्यन्नाह ब्रह्मोपाप्नवानीति ।ब्रह्मैवो-पाप्नोति ॥ १ ॥
In plain words
Om is Brahman. Om is this entire universe. Om is an assent; as when they say 'Cause to listen,' they cause to listen with Om. With Om they sing the Sāman chants. With Om they recite the Śastras. With Om the Adhvaryu priest gives his response. With Om the Brahmā priest gives permission. With Om the Agnihotra is sanctioned. With Om the Brāhmaṇa, about to commence study, says, 'May I attain Brahman.' He attains Brahman indeed.
Close to the Sanskrit
Om is Brahman. Om is this all. Om this is imitation indeed, saying 'Cause to listen' they cause to listen. Om they sing sāman chants. Om śom they recite śastra hymns. Om the adhvaryu priest responds with pratigara. Om the brahmā priest permits. Om he approves the agnihotra. Om the brāhmaṇa about to recite says 'May I attain Brahman.' He attains Brahman indeed.