Sahih Muslim
The Book of Faith (Kitab Al-Iman)
Book Number: 001 / Hadith Number: 412
Abu Sa'id al-Khudri reported: Verily, the Messenger of Allah (may peace be upon him) said: The least tormented of the inhabitants of the Fire would be he who would wear two shoes of Fire and his brain would boil on account of the heat of the shoes.