Chapter 18 · verse 37 · gita.yoga.org

Bhagavad Gita 18.37

यत्तदग्रे विषमिव परिणामेऽमृतोपमम्।तत्सुखं सात्त्विकं प्रोक्तमात्मबुद्धिप्रसादजम्

That which is like poison at first but in the end like nectar—that happiness is declared to be sattvic, born of the purity of one's own mind due to self-realization.