Mahabharata 8.49.18

न हि कार्यमकार्यं वा सुखं ज्ञातुं कथंचनश्रुतेन ज्ञायते सर्वं तच्च त्वं नावबुध्यसे

na hi kāryamakāryaṃ vā sukhaṃ jñātuṃ kathaṃcanaśrutena jñāyate sarvaṃ tacca tvaṃ nāvabudhyase

Our plain-language meaning of this verse is waiting for scholar review.