Hadith 95
أجروكم على الفتيا أجروكم على النار
"The one among you who is the most daring in giving fatwas is also the most daring among you in entering the fire of Hell. (This means that one should be cautious in giving fatwas, avoid haste, lest an incorrect fatwa is issued without proper investigation, which may become a cause for entering Hell.)"
