Bhagavadgeeta Verse 2.38
सुख दुःखॆ समॆ कृत्वा लाभ-अलाभौ जय-अजयौ
ततः युद्धाय युज्यस्व न एवं पापं अवाप्स्यसि ॥ २.३८ ॥
ಸುಖ ದುಃಖೇ ಸಮೇ ಕೃತ್ವಾ ಲಾಭ-ಅಲಾಭೌ ಜಯ-ಅಜಯೌ
ತತಃ ಯುದ್ಧಾಯ ಯುಜ್ಯಸ್ವ ನ ಏವಂ ಪಾಪಂ ಅವಾಪ್ಸ್ಯಸಿ || ೨.೩೮ ||
sukha duHkhE samE kRutvA lAbha-alAbhau jaya-ajayau
tataH yuddhAya yujyasva na EvaM pApaM avApsyasi || 2.38 ||
Considering pleasure and pain, gain and loss, victory and defeat as equal, prepare yourself for battle; thereby you shall not incur sin at all.
Having shunned the passion for pleasure, etc, and considering this natural duty to be the worship of Lord, you should make yourself ready for the battle.
Fighting with the belief that it is your own proper duty, and with devotion to the glorious Lord, you shall not be committing any sin; merit alone will accrue to you.
sukha duHkhE samE kRutvA = Treating sensual happiness opposed to Moksha and as equally an obstacle for Moksha as sorrow is an obstacle. It does NOT mean treating sensual happiness and spain as equal.