Abu Ishaq (may Allah have mercy on him) said: I was sitting with Abd al-Rahman bin Abdullah (bin Mas'ud) (may Allah have mercy on him), when a man came to him and asked him about his son al-Qasim. He said: "He went early in the morning to al-Kunasah (the refuse-dumping ground) looking for dabb (lizards)." The man said: "Do you eat it?" Abd al-Rahman said: "And who has made it unlawful? I heard Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) say: 'The one who declares the lawful to be unlawful is like the one who declares the unlawful to be lawful.'"
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8821