दैवमेवापरे यज्ञं योगिनः पर्युपासते।
ब्रह्माग्नावपरे यज्ञं यज्ञेनैवोपजुह्वति।।4.25।।
Other yogis perform yajna to devatas alone, Others offer the atman by the atman itself, in the fire of Brahman.
A few verses are started in order to do the stuti of jnana-yajna. Bhagvan says here that a yajna through which devatas are propitiated is known as daiva-yajna. Other yogis i.e. karmis (not involved in jnana-yajna) perform those daiva-yajnas alone.
By the word Brahman is meant the one who is devoid of all samsara-dharma like hunger and thirst, who remains after negating all visheshas as depicted in Neti-Neti and who is described as ‘Satyam, Jnanam, Anantam’, ‘Vijnanam, Anandam’, ‘That which is direct and aparoksha Brahman, which is the inner atman of all’ etc.
That which is Brahman, is fire. Brahman is stated as fire in order to explain it as an adhikaran ( = receptacle) of oblation.
Others i.e. the Brahma-vit offer yajna (Y1) into Brahma-Agni by yajna (Y2). Atman is meant from the word Y1. This is so because there is a mention of the word ‘yajna’ in the names of atman (so yajna is a synonym of atman). This atman yajna Y1 is Param Brahman alone in paramartha but being buddhi-aadi-upadhi-samyukta, all upadhi dharma are adhyasta in it. This Y1 is the oblation.
Y2 is this same Y1 as enumerated. Brahma-vit offers Y1 atman through Y2. This offering of yajna by yajna in Brahman-fire means the seeing of the atman along with upadhis as the Param Brahman devoid of all upadhis in swaroopa. Those sanyasis who are Brahma-Atman-Ekatva-Darshan-Nishth do this offering. That is the meaning.
This yajna having the lakshana of samyak-darshan is introduced by the instant verse and is included among yajnas such as daiva-yajna for the stuti (of samyak-darshan) by way of Gita 4.33 etc.
In the second line of the shloka, the word yajna refers to atman. This atman is the one in which the upadhi-dharmas are adhyasta. A Brahma-vit offers such atman by atman in Brahman. The essence is that he sees the swaroopa of such atman as Brahman.