1310
Śrīmad-Bhāgavatam
[ Canto 3, Ch. 30 ]
classifications of castes, or  varṇas , according to quality and work. Apart from  Bhagavad-gītā , 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  varṇas , namely  brāhmaṇa ,  kṣatriya ,  vaiśya  and  śūdra . In  Bhagavad-gītā  and in other Vedic literatures, the specific duties of the  brāhmaṇa ,  kṣatriya ,  vaiśya  and  śūdra  are mentioned.
One should work honestly according to his qualification. He should not earn his livelihood unfairly, by means for which he is not qualified. If a  brāhmaṇa  who works as a priest so that he may enlighten his followers with the spiritual way of life is not qualified as a priest, then he is cheating the public. One should not earn by such unfair means. The same is applicable to a  kṣatriya  or to a  vaiśya . It is especially mentioned that the means of livelihood of those who are trying to advance in  Kṛṣṇa  consciousness must be very fair and uncomplicated. Here it is mentioned that he who earns his livelihood by unfair means ( kevalena ) is sent to the darkest hellish region. Otherwise, if one maintains his family by prescribed methods and honest means, there is no objection to one's being a family man.
TEXT 34
अधस्तामरलोकस्य यावतीर्यातनादयः । 
  क्रमशः समनुक्रम्य पुनरत्राम्रजेच्छुचिः ॥३४॥
adhastān nara-lokasya 
  yāvatīr yātanādayaḥ 
  kramaśaḥ samanukramya 
  punar atrāvrajec chuciḥ
adhastāt—from below; nara-lokasya—human birth; yāvatīḥ—as many; yātanā—punishments; ādayaḥ—and so on; kramaśaḥ—in a regular order; samanukramya—having gone through; punaḥ—again; atra—here, on this earth; āvrajet—he may return; śuciḥ—pure.
TRANSLATION
Having gone through all the miserable hellish conditions and having passed in a regular order through the lowest forms of animal life prior to