माहण कुल संभूओ, आसी विप्पो महाजसो । जायाई जम्मजण्णिमि, जयघोसिति णामओ ॥२५.१॥
Born of Brahmin lineage, there was a greatly renowned Brahmin named Jayaghosha, who performed yama-niyama as his yajna (sacrifice).
The chapter opens by introducing Jayaghosha: a Brahmin by birth but a Jain monk by inner realization. The key phrase is jammajāṇṇimi — one for whom the ethical restraints (yama-niyama: ahiṃsā, satya, asteya, brahmacarya, aparigraha) constitute the real yajna. This immediately sets the philosophical axis of the chapter: the Śramaṇa tradition's inner sacrifice vs. the Brahmanical tradition's outer fire-ritual.
The simple version: Jayaghosha was a famous Brahmin who had become a Jain monk — and his "sacrifice" was not a fire ritual but the daily practice of non-violence and self-control.