Bhagavad Gita Chapter 4.12
kāńkṣantaḥ karmaṇāḿ siddhiḿ
yajanta iha devatāḥ
kṣipraḿ hi mānuṣe loke
siddhir bhavati karma-jā
Translation
Men in this world desire success in fruitive activities, and therefore they worship the demigods. Quickly, of course, men get results from fruitive work in this world.