1 Gita Sloka Every Day - Chapter 18 - Moksha Sanyasa Yoga - Sloka 42

The entire content of this mail is from Shri V N Gopala Desikan's  Srimad Bhagavad Gita, published by Vishishtadvaita Research Centre, Chennai and The Bhagavad Gita by Swami Chidbhavananda published by Ramakrishna Mission

The distinctiveness of each varna as evinced by its svadharma is delineated as follows:

1 Gita Sloka  Every Day - Chapter 18 - Moksha Sanyasa Yoga - Sloka 42

Sudama the brahmin friend of Krishna

Samah damah tapah shoucham kshantih arjavam eva cha I

Jnanam vijnanam astikyam brahma karma svabhavajam II sloka 42

सामः दमः तपः शौचं क्षान्तिः आर्जवं एव च I 
ज्ञानं विज्ञानं आस्तिक्यं ब्रह्म कर्म स्वभावजं II श्लोक 42

Serenity, self restraint, austerity, purity, forgivenss and also uprightness, knowledge, realisation, belief in the hereafter - these are the duties of teh Brahmanas, born of their own nature.

He is a brahmana who is imbued with qualities all conducive to a spiritual life. Self control and self discipline are as natural and agreeable to him as water is to a duckling. His mind being turned to sublime and supramundane concerns, serenity is the norm with him. He cannot afford to be flippant with the trifles. Sense control is a moral warfare to the ordinary man; but to the brahmana it is a matter of course. Sublimation of the body, mind and speech is austerity. This merit finds its full expression in this spiritual man. A thing that retains its original state is said to preserve its purity. The spiritual man is fixed in the feeling that he is atman. His body and the senses behave in tune with this divine feeling. The even tenor of the spiritual life of a god man is bound to be affected once in a way at least by the intrusion of the worldly people. But he is never affected thereby not does he ever think of retaliating or resisting. Calm forgiveness sis his way. His thought word and deed being ever directed to the welfare of all, there is uprightness in every bit of action. He is as trustworthy to people as the mother is to her baby.The brahmana begins his life with scriptural knowledge in regard to god and his creation;and he fulfils it with intuitive knowledge or god realization. Any amount of scriptural knowledge without this avails nothing. Asitkya is more than a formal belief in God and hereafter. It is a burning faith in the divine aspect of life and in its eternity.A brahmana holds himself as a pilgrim on earth and not as one belonging to it. His treasure is not of the mundane but of the divine. A simple living with bare earthly possession distinguishes him from others. To decorate the body is not in his way. He loves all beings alike and claims a universal kinship. And these are the marks of a brahaman. As the brahmanas increase in number, the ethical and spiritual standards of the society go up.