“Karmanye vadhikaraste…”– Can We Justify the Sermons?

“कर्मण्येवाधिकारस्ते माफलेषुकदाचन ।
माकर्मफलहेतुर्भूर्मा ते सङ्गोस्त्वकर्मणि ।।”

Karmanye vadhikaraste Ma Phaleshu Kadachana ।
Ma Karmaphalaheturbhurma Te Sangostvakarmani ।।

— Sreemad Bhagawad Geeta, 2nd Chapter, Stanza 47.

It is well known that these devices and dialogues were delivered to the great warrior Arjuna by Lord Sri Krishna; however, the exact date of the conversation is still a mystery. Since time immemorial, people are following these verses from the holy book of Shreemad Bhagwad Geeta.

The stanza preaches “You have a right to perform your prescribed duties, but you are not entitled to the fruits of action or the outcome of your deeds. Let not the results or the outcomes be the motivation, and never should you be so attached to the outcomes neither should you be attracted to inaction.
But, how many of us do not expect any kind of result from the tasks we perform? We all are human beings and each of us has aims and ambitions, which make us, expect fruitful results for what we do. The good deeds may provide us positive results, while the bad deeds may lead to terrible results. Irrespective of the performances, we anticipate some or the other results from our deeds. The results may be nectar or poison to the performer.
Hence, the literal meaning of the stanza leads to confusion; how can I determine if I should do a job without knowing its result? Can we justify the sermons of Lord Sri Krishna to Arjuna?