Before the coming of Muhammad, the last of the Prophets, Almighty God had given intimation of his advent through the previous prophets. These prophecies were found in the revealed books of the past, and may still be read, even today, in spite of all the alterations made to these books throughout the ages. This remains the most powerful argument in support of the veracity of the final Prophet. But, in order to understand the power of reasoning, seriousness is required—a rare phenomenon in this world.