Some yogis devote themselves only to sacrifice offered to the gods. Others offer the sacrifice itself, by means of sacrifice, into the fire of Brahman.
Explanation
Krishna has just described the sacrifice (yajña) in which every part of the act is seen as Brahman. Now he lists different kinds of sacrifice that practitioners follow, beginning with ritual offerings to the gods (deva) and then a subtler kind. The second line is read in different ways: Advaita commentators take it as offering the self into Brahman, while others take it as offering one act of worship through another as worship of the Divine.