18.41 Parantapa, O scorcher of enemies; karmani, the duties; brahmana-ksatriya-visam, of the Brahmanas, the Ksatriyas and the Vaisyas; ca, as also; sudranam, of the Surdras-the Sudras have not been included with the others (in the compund word) because, owing to their having a single birth, [Sudras have no right to be invested with the sacred thread which, in the case of the other three castes, symbolizes a second birth.] they have no right to (the study of) the Vedas; pravibhaktani, have been fully classified, have been prescribed by making distinctions among them;-according to what?-gunahi, according to the gunas; svabhava-prabhavaih, born from Nature.
Nature means the Praktrti of God, His Maya consisting of the three gunas. 'Born from Nature' means 'born of these three gunas. In accordnace with these the duties such as control of the internal organs, etc. of the Brahmanas and others have been classified. Or (the meaning is): The source of the nature of the Brahmanas is the ality of sattva. Similarly, the source of the nature of the Ksatriyas is rajas, with sattva as a subordinate (ality); the source of the nature of the Vaisyas is rajas, with tamas as the subordinate (ality); the source of the nature of the Sudras is tamas, with rajas as the subordinate (ality); for the natures of the four are seen to be tranillity. lordliness, industriousness and dullness respectively. Or, svabhava (nature) means the (individual) tendencies of creatures earned in their past lives, which have become manifest in the present life for yielding their own results. The gunas which have that svabhava as their source (prabhava) are svabhava-prabhavah gunah.
Since the manifestation of the gunas cannot logically be uncaused, therefore a specific cause [i.e. the tendencies are the efficient cause, and Nature is the material cause.] has been posited by saying that Nature is the cause.
Thus, the duties such as control of the internal organs etc. have been classified in keeping with the effects of the gunas, sattva, rajas and tamas, which are born of Nature, born of Prakrti.
Objection: Well, are not the duties like controlling the internal organs etc. of the Brahmanas and others classified and enjoined by the scriptures? Why is it said that they are classified according to the gunas sattva etc.?
Reply: This objection is not valid. For, the duties like controlling the internal organs etc. of the Brahmanas and others have been classified even by the scriptures verily in keeping with the specific alities sattva etc.; certainly, not without reference to the gunas. Hence, though the duties have been divided by the scriputres, they are said to have been classified according to the gunas.
Which, again, are those duties? They are being spoken of: