sva-dharma-stho yajan yajñair
na yati svarga-narakau
yady anyan na samacaret
My dear Uddhava, a person who is situated in his prescribed duty, properly worshiping by Vedic sacrifices but not desiring the fruitive result of such worship, will not go to the heavenly planets; similarly, by not performing forbidden activities he will not go to hell.
The perfection of karma-yoga is described here. One who does not desire fruitive rewards for his religious activities does not waste time going to the heavenly planets for celestial sense gratification. Similarly, one who does not neglect his prescribed duty or perform forbidden activities will not be bothered by going to hell for punishment. Thus avoiding material rewards and punishments, such a desireless person can be promoted to the platform of pure devotional service to Lord Krsna.