Bhagavad Gita 3.9
यज्ञार्थात्कर्मणोऽन्यत्र लोकोऽयं कर्मबन्धनः। तदर्थं कर्म कौन्तेय मुक्तसङ्गः समाचर।।3.9।।
yajñārthātkarmaṇo'nyatra loko'yaṃ karmabandhanaḥ| tadarthaṃ karma kaunteya muktasaṅgaḥ samācara||3.9||
yajnarthatkarmano'nyatra loko'yam karmabandhanah tadartham karma kaunteya muktasangah samacara3.9
Meaning
Work done as a sacrifice for the Supreme frees one from bondage. All other work binds the living entity to the material world. Therefore, perform your duties as an offering to God, free from selfish attachment.
यज्ञ के लिये किये हुए कर्म के अतिरिक्त अन्य कर्म में प्रवृत्त हुआ यह पुरुष कर्मों द्वारा बंधता है इसलिए हे कौन्तेय आसक्ति को त्यागकर यज्ञ के निमित्त ही कर्म का सम्यक् आचरण करो।
This is verse 9 of 43 in Chapter 3 (Karma Yoga) of the Bhagavad Gita.