SB 7.15.66
yad yasya vanisiddham syad
yena yatra yato nrpa
sa teneheta karyani
naro nanyair anapadi
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
In normal conditions, in the absence of danger, O King Yudhisthira, a man should perform his prescribed activities according to his status of life with the things, endeavors, process and living place that are not forbidden for him, and not by any other means.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
This instruction is given for men in all statuses of life. Generally society is divided into brahmanas, ksatriyas, vaisyas, sudras, brahmacaris, vanaprasthas, sannyasis and grhasthas. Everyone must act according to his position and try to please the Supreme Personality of Godhead, for that will make one’s life successful. This was instructed in Naimisaranya:
atah pumbhir dvija-srestha
varnasrama-vibhagasah
svanusthitasya dharmasya
samsiddhir hari-tosanam
“O best among the twice-born, it is therefore concluded that the highest perfection one can achieve, by discharging his prescribed duties [dharma] according to caste divisions and order of life, is to please the Lord Hari.” (Bhag. 1.2.13) Everyone should act according to his occupational duties just to please the Supreme Personality of Godhead. Then everyone will be happy.