Reference: Siyar A’laam an-Nubalaa – Volume 8, Page 48
Abu Thowr narrated he heard ash-Shaafi’ee saying that if some of the people [who practice their religion based upon] desires came to Maalik [ibn Anas], he would say [to them]:
Indeed, in terms of my religion I am upon sound proof, and as for you, then you are upon doubt; go to one who is upon doubt as you are – and debate with him.