Bhagavad Gita · Chapter 2: The Path of Understanding

Bhagavad Gita 2.49

dūreṇa hyavaraṃ karma buddhiyogāddhanañjaya | buddhau śaraṇamanviccha kṛpaṇāḥ phalahetavaḥ ||

Action done for results is far inferior to the discipline of understanding, Arjuna. Seek refuge in understanding. Those whose motive is the result are to be pitied.

Modern context

Work done only for what it will bring is far inferior to work done with an even understanding. Krishna calls those who live for results 'pitiable', and the word is exact: they have handed their peace to things they do not control. Each success leaves them needing the next one.