Hadith is the sayings and actions of the prophet Muhammad, it is considered along with the Quran the main sources of all Islamic Laws.
"I am Muhammad, I am Ahmad, I am the effacer and infidelity shall be erased through me; I am the assembler. People shall be assembled on Doomsday after my time. (In other words Doom is my only successor.) And I am the last in the sense that no prophet shall succeed me."