Bhagavatapurana 8.6.20

8.6.20

arayo 'pi hi sandheyāḥ sati kāryārthagaurave /
ahimūṣikavaddevā hy arthasya padavīṃ gataiḥ //

20. When the object to be accomplished is great, alliance should be made even with enemies, O gods, by those that have sought the path of gaining their object just as the serpent does with the rat.