Al-Imaam Al-Haafith Abu Khaythamah Zuhayr bin Harb An-Nisaa-ee (may Allaah have mercy upon him) reported in his book "Kitaabul-Ilm":
Al-Fadl bin Dukayn informed me, on the authority of Sufyaan Ath-Thawree, on Yahyaa bin Sa'eed, that he said: I heard Al-Qaasim bin Muhammad say:
"The man that lives as one who is ignorant is better for him, then giving a religious verdict regarding that which he has no knowledge of."
Source: Kitaabul-Ilm Maktabah Ibn Abbaas Narration #91 pg.104
Sisters Upon Al-Istiqaamah