8:13  

ओमित्येकाक्षरं ब्रह्म व्याहरन्मामनुस्मरन् ।
यः प्रयाति त्यजन्देहं स याति परमां गतिम् ॥८- १३॥

ओmityekaakSharaM brahma wyaaharanmaamanusmaran ।

yaH prayaati tyajandehaM sa yaati paramaaM gatim ॥८- १३॥

Source: Automatic ITRANS Transliteration

Uttering aum the monosyllable [of] Brahman, meditating on Me,
Who passes out of the body, they attain transcendence.

Source: Milind S. Pandit

One who leaves the body while meditating on Brahman and uttering OM, the sacred monosyllable sound of Brahman, attains the Supreme goal.

Source: The Bhagavad-Gita: The Sacred Song

After being situated in this yoga practice and vibrating the sacred syllable om, the supreme combination of letters, if one thinks of the Supreme Personality of Godhead and quits his body, he will certainly reach the spiritual planets.

Source: Bhagavad Gita As It Is