Krishna begins with definitions. The wise call sannyasa the complete renunciation of desire-driven actions — those things you do only because you want something in return. Tyaga, on the other hand, means continuing to act but releasing your grip on the results. The difference is sharp: one drops the action itself, the other drops the craving that clings to it.
Think of a farmer who plants rice every season. If he stops farming altogether because he once had a bad harvest, that is more like sannyasa of action — walking away entirely. But if he keeps planting with full care, rain or drought, and does not lose sleep over whether the yield will double this year, that is tyaga. The hands stay busy. The mind stays free.
This distinction runs through the rest of the chapter. Krishna will make clear which path he recommends — and it is not the one that involves walking away.