Although a medicinal herb, being born in the forest, does not belong to the same category as a man, if beneficial it is kept very carefully. Similarly, if someone outside one’s family is favorable, he should be given protection like a son. On the other hand, if a limb of one’s body is poisoned by disease, it must be amputated so that the rest of the body may live happily. Similarly, even one’s own son, if unfavorable, must be rejected, although born of one’s own body.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
परोऽप्यपत्यं हितकृद्यथौषधं स्वदेहजोऽप्यामयवत्सुतोऽहितः । छिन्द्यात्तदङ्गं यदुतात्मनोऽहितं शेषं सुखं जीवति यद्विवर्जनात्
paro'pyapatyaṃ hitakṛdyathauṣadhaṃ svadehajo'pyāmayavatsuto'hitaḥ | chindyāttadaṅgaṃ yadutātmano'hitaṃ śeṣaṃ sukhaṃ jīvati yadvivarjanāt
SB 7.5.37