Rajatarangini (Dvitiya) 16

16

kavīnām upayogyā vā madvāk svāntaraśuddhaye /
Gaṅgājalaṃ jalaṃ teṣāṃ yair na pītaṃ jalāntaram //

Or my speech may be useful to poets for purifying their own inner self; / the water of the Gaṅgā is water to those who have drunk no other water.