Bhagavad Gita 17.25
Those who desire deliverance begin their acts of sacrifice, austerity, or gift with the word "Tat" (meaning "That"), without thought of reward.
तदित्यनभिसन्धाय फलं यज्ञतपःक्रियाः।दानक्रियाश्च विविधाः क्रियन्ते मोक्षकाङ्क्षि॥tadityanabhisandhāya phalaṃ yajñatapaḥkriyāḥ|dānakriyāśca vividhāḥ kriyante mokṣakāṅkṣi||
English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).