Bg 3.35

śreyān sva-dharmo viguṇaḥ
para-dharmāt sv-anuṣṭhitāt
sva-dharme nidhanaṁ śreyaḥ
para-dharmo bhayāvahaḥ

Word for word: 

śreyān — far better; sva–dharmaḥ — one’s prescribed duties; viguṇaḥ — even faulty; para–dharmāt — than duties mentioned for others; su–anuṣṭhitāt — perfectly done; sva–dharme — in one’s prescribed duties; nidhanam — destruction; śreyaḥ — better; para–dharmaḥ — duties prescribed for others; bhaya–āvahaḥ — dangerous.

Translation: 

It is far better to discharge one’s prescribed duties, even though faultily, than another’s duties perfectly. Destruction in the course of performing one’s own duty is better than engaging in another’s duties, for to follow another’s path is dangerous.

 

(sometimes people take some small quote of BG and use for their our sense some Hindu org who are trying to get back converted Hindus use this verse … Par Dharma Bhayavah… actually Krishna is not referring to Hindu or Christianity etc none of these religion where there at Vedic time)

If a person is Brahmana it is better to be Brahmana then acting as Kshetriya in general thus they will be purified.

In reply to Arjuna’s question on how one overcomes sinful desire, Krishna is saying to practice Karma Yoga which means to regulate ones Kama otherwise there will not be much yoga it will be only Karma Kanda or just Karma. To do perform nishkam karma yoga…attraction and aversion should be regulated.