By honest means
Srimad-Bhagavatam
SB Canto 2
There is no harm if one becomes the richest man in the world by honest dealings, but one should not sacrifice the honest means of livelihood simply to accumulate wealth.
SB 2.8.21, Purport: One should also not accumulate money to become puffed up in the material world. One should earn his livelihood easily and honestly, for it is better to become a coolie for an honest livelihood than to become a great man in society by hook and crook. There is no harm if one becomes the richest man in the world by honest dealings, but one should not sacrifice the honest means of livelihood simply to accumulate wealth. Such an endeavor is harmful to devotional service.