1) The Quran and hadith prohibit riba (usury), describing those who engage in it as resembling those beaten by Satan into insanity and as being cursed to dwell in Hellfire. 2) Specific prohibitions mentioned include gold for silver except hand to hand in equal amounts, wheat for wheat except hand to hand in equal amounts, dates for dates except hand to hand in equal amounts, and barley for barley except hand to hand in equal amounts. 3) Hadith also describe a punishment in the afterlife of those who engage in riba, with a man in a river of blood being unable to escape as another continuously throws stones in his mouth.