Bhagavad Gītā Chapter Eight verse 13

om ity ekākṣaraṃ brahma vyāharan mām anusmaran |

yaḥ prayāti tyajan dehaṃ sa yāti paramāṃ gatim ||

om - mystical symbol, sacred exclamationbrahman - that which expands; the absolute, the eternalparama - highest, most