The wise should strive only for that which is not obtained by those who wander up and down (in samsara). For material happiness comes of its own accord, just as misery does, through the deep current of time.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
तस्यैव हेतोः प्रयतेत कोविदो न लभ्यते यद्भ्रमतामुपर्यधः। तल्लभ्यते दुःखवदन्यतः सुखं कालेन सर्वत्र गभीररंहसा॥
tasyaiva hetoḥ prayateta kovido na labhyate yad bhramatām upary adhaḥ tal labhyate duḥkhavad anyataḥ sukhaṁ kālena sarvatra gabhīra-raṁhasā
SB 1.5018