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ब्रह्मार्पणं ब्रह्म हविर्ब्रह्माग्नौ ब्रह्मणा हुतम् ।
ब्रह्मैव तेन गन्तव्यं ब्रह्मकर्मसमाधिना ॥४-२४॥

brahmaarpaNaM brahma hawirbrahmaagnau brahmaNaa hutam ।

brahmaiwa tena gantawyaM brahmakarmasamaadhinaa ॥४-२४॥

Source: Automatic ITRANS Transliteration

The offering is Brahma, the act of offering is Brahma, in the Brahma-fire sacrificed to Brahman.
To Brahma itself thereby must [one] go, in the trance of Brahma-action.

The offering is Brahma, the act of offering is Brahma, sacrificed to Brahman in the fire that is Brahma. Thereby, in a trance of Brahma-action must [one] go to none other than Brahma.

(See also 9.16.)

Source: Milind S. Pandit

Brahman is the oblation. Brahman is the clarified butter. The oblation is poured by Brahman into the fire of Brahman. Brahman shall be realized by the one who considers everything as (a manifestation or) an act of Brahman. (Also see 9.16)

Source: The Bhagavad-Gita: The Sacred Song

A person who is fully absorbed in Krsna consciousness is sure to attain the spiritual kingdom because of his full contribution to spiritual activities, in which the consummation is absolute and that which is offered is of the same spiritual nature.

Source: Bhagavad Gita As It Is