The Dangers of Mocking the Symbols Which The Creator Revealed

From an English study circle focused on a chapter of 'The Book of Monotheism'. We love and respect free speech. However, the relation between free speech and freedom of worship is in a constant dynamic relation. Certainly no one should be forced to censor their criticism of a religion they do not believe. What events in the time of the prophet Muhammad (upon whom I invoke peace and blessings) sheds light on the relation between free speech and religion? How did the prophet react to those who ridiculed him?