Those who partake of the nectarine remains of yajña, reach the eternal Brahman. O best of Kurus, for one devoid of the yajña-spirit and pursuit, benefits of this world are not there; how then of the other.
If one is involved in yajña of one kind or another, all his activities and pursuits become greatly holy, equal to sacrifice. And whatever he gets and partakes of becomes the residual product of yajña. This means he is having yajña-prasāda, which makes him pure, holy and divine. And he attains Brahman.
Krishna significantly adds: This world is only meant for one given sincerely to performing yajña. Any negligence shown in this regard is inexcusable. It will only lead to his downfall, and nothing can save him from the calamity. About the indispensable need for performing yajña, Krishna already stated (3.10), linking it to Prajapati, who enjoined the pursuit of yajña for the humans.
This world itself stands lost for one who does not do yajña. How can another world be then thought of!