Knowledge (Kitab Al-Ilm)
Dawud :: Book 25 : Hadith 3649
Narrated AbuHurayrah:
The Prophet (peace_be_upon_him) said: If anyone is given a legal decision ignorantly, the sin rests on the one who gave it. Sulayman al-Mahri added in his version: If anyone advises his brother, knowing that guidance lies in another direction, he has deceived him. These are the wordings of Sulayman.