In texts 19-22, Krishna explained how to achieve "inaction" (freedom from reaction) by action performed in the proper state of mind. Here, in Text 23, he says that since such right-minded action is free from reaction, it is equivalent to religious sacrifice (yajna).
Yajnacharatah karma - Work as an act of sacrifice
The word yajna is a Sanskrit name for God (Vishnu). It also means sacrifice, since sacrifice is an act done for the pleasure of God.
Considering the two aspects of this word, the phrase yajnacaratah karma has two important meanings: (1) it means that right-minded action is equivalent to religious sacrifice; and (2) it means that action (karma) becomes most perfect when it is not only selfless, but performed as an act of sacrifice to please the Supreme Lord.
Samagram praviliyate - Entirely dissolves
Work performed as a sacrifice for Gods pleasure has no material reaction. Indeed, the reactions are completely (samagram) destroyed (praviliyate).