Mahabharata 12.174.14

आत्मना विहितं दुःखमात्मना विहितं सुखम्गर्भशय्यामुपादाय भुज्यते पौर्वदेहिकम्

ātmanā vihitaṃ duḥkhamātmanā vihitaṃ sukhamgarbhaśayyāmupādāya bhujyate paurvadehikam

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