verse 38

सुखदु:खे समे कृत्वा लाभालाभौ जयाजयौ |
ततो युद्धाय युज्यस्व नैवं पापमवाप्स्यसि || 38||

Then, treating alike pleasure and pain, gain and loss, success and
defeat, prepare for the battle, and thus wilt thou not incur sin.

Krishna tells Arjuna that as long as his actions are motivated by his
commitment to his duties he will not incur sin. Do the right thing and
merit is guaranteed for you.

Here Krishna is saying that the normal way of thinking where success
leads to gain and pleasure, while defeat leads to pain and loss, is
self-centered. Doing your Svadharma (स्वधर्म) will always leads to merit.