Bhagavad Gita Verse 7, Chapter 5

yogayukto vishuddhaatmaa vijitaatmaa jitendriyaha |
sarvabhootaatmabhootaatmaa kurvannapi na lipyate || 7 ||
 
One who is established in yoga, who has conquered the mind, body and senses, one who sees his own self in all beings, even while acting is not tainted.
 
yogayuktaha : established in yoga
vishuddhaatmaa : one with pure mind
vijitaatmaa : one who has conquered the body
jitendriyaha : one who has control over senses
sarvabhootaatmabhootaatmaa : one who sees his own self in all beings
kurvan : while acting
na : does not
api : even while
lipyate : tainted
 
Imagine that a new factory has opened up in a small town, and the public has been invited to take tours of the factory. In one such tour, we have a businessman, an environmentalist, an engineer and a musician. As he is walking through the factory, the businessman's first thought is about the amount of profit that this factory generates. The environmentalist thinks about the pollution caused by the factory. The engineer marvels at the brand new machines. And the musician loves the rhythm generated by the clanking machines. One's vision gives an indication of how one's mind works.
 
In this shloka, Shri Krishna illustrates the vision of one who is acting with the spirit of karma yoga. Even while acting, that person does not generate any further desires, because he has the same vision that a renouncer has. He sees the eternal essence everywhere, in himself as well as in everyone else. And like the example we saw earlier, his vision indicates that his entire personality, including his mind and intellect, have gained the knowledge of the eternal essence.
 
Furthermore, Shri Krishna reminds us that such knowledge is not possible without first bringing the body, mind and senses under control. Actions performed by such an individual do not "taint" him. Only when the sense of doership and enjoyership is present can actions can taint someone, in other words, cause further desires to sprout. When the ego behind actions has gone away, then those actions do not generate further desires.