Srimad-Bhagavatam: Canto 7 - Chapter 1 - Verse 30
Sanskrit:
श्रीभगवानुवाचमैवं विभोऽसुराणां ते प्रदेय: पद्मसम्भव ।वर: क्रूरनिसर्गाणामहीनाममृतं यथा ॥ ३० ॥
ITRANS:
śrī-bhagavān uvācamaivaṁ vibho ’surāṇāṁ tepradeyaḥ padma-sambhavavaraḥ krūra-nisargāṇāmahīnām amṛtaṁ yathā
Translation:
The Personality of Godhead replied: My dear Lord Brahmā, O great lord born from the lotus flower, just as it is dangerous to feed milk to a snake, so it is dangerous to give benedictions to demons, who are by nature ferocious and jealous. I warn you not to give such benedictions to any demon again.