Sayyiduna Anas bin Malik (may Allah be pleased with him) says that I heard the Messenger of Allah (peace and blessings be upon him) say: "O people! Weep, and if you do not weep, then make a weeping face. Surely, the people of the Fire will weep in the Fire until their tears flow down their faces like small streams of irrigation, until their tears run out, then blood will flow. Their eyes will be wounded, and if indeed boats are sailed in them, they will certainly sail."