What makes a sacrifice sattvic? Krishna lays out two conditions. First, it follows the rules prescribed in scripture. Second, the person performing it has no desire for any personal reward. The only thought in their mind is: this is my duty.
A sattvic sacrifice is free from bargaining. The person does not offer prayers hoping for a promotion, a son, or a windfall. They offer because it is right to offer — the way a farmer sows seeds in the right season because that is what a farmer does.
The Gita's definition of yajna is broader than a fire ritual. Any selfless act done out of duty, without expecting return, qualifies. A mother caring for her child without keeping score carries the same spirit as a sattvic yajna.