From Sahih Bukhari (Hadith 3524):
Narrated Ibn `Abbas:If you wish to know about the ignorance of the Arabs, refer to Surat-al-Anam after Verse No. 130:-- Indeed lost are those who have killed their children From folly without knowledge and have forbidden that which Allah has provided for them, inventing a lie against Allah. They have indeed gone astray and were not guided
Reference: Bukhari 3524