Three words in this verse are very significant. Kevalena means only by black methods, adharmena means unrighteous or irreligious, and kutumba-bharana means family maintenance. Maintaining ones family is certainly the duty of a householder, but one should be eager to earn his livelihood by the prescribed method, as stated in the scriptures. In Bhagavad-gita it is described that the Lord has divided the social system into four classifications of castes, or varnas, according to quality and work. Apart from Bhagavad-gita, in every society a man is known according to his quality and work. For example, when a man is constructing wooden furniture, he is called a carpenter, and a man who works with an anvil and iron is called a blacksmith. Similarly, a man who is engaged in the medical or engineering fields has a particular duty and designation. All these human activities have been divided by the Supreme Lord into four varnas, namely brahmana, ksatriya, vaisya and sudra. In Bhagavad-gita and in other Vedic literatures, the specific duties of the brahmana, ksatriya, vaisya and sudra are mentioned.