Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
Simplest terms, brass tacks and bottom line, that means that the Government cannot tell you
1) what to think
2) what to say
3) who to say it to.
They cannot tell you, force you, or coerce you in any of your most personal beliefs, nor can they prevent you from giving voice to those beliefs, and they don't get to decide who you hang out with in order to discuss those beliefs.
They can limit conduct, especially if there is a clear and present danger of harm, and remember that a Democracy has the right and authority to fight back against actions that can harm it (pity the Weimar Republic didn't learn that lesson).
Lots of court cases have defined what limits can be placed on certain dangerous expressions (shouting 'fire' in a crowded theater, so-called "fighting words", intimidation, etc.), but absent the clear harm or threat of harm to another, the government does NOT get to tell you what to believe, what to say (or print out), and who your friends are. Those most basic of tenets must be defended.
And if it is a case of my neighbor trying to build a church on his property that crosses over our shared fence line, I would expect the police and courts to limit his expression insofar as it infringes upon my own rights, using force if necessary.
But what if it is the Government that is doing the infringing upon those rights? What fallback position do we have in those cases?
Relax, that's the next Amendment. Our Founders had just used all those "hunting tools" to kick out the most powerful Empire on the planet at that time.
The Second Amendment is a doomsday provision, one designed for those exceptionally rare circumstances where all other rights have failed - where the government refuses to stand for reelection and silences those who protest; where courts have lost the courage to oppose, or can find no one to enforce their decrees. However improbable these contingencies may seem today, facing them unprepared is a mistake a free people get to make only once. -- Justice Alex Kozinski, Ninth Circuit Court, in his dissent to Silveria v. Lockerand
The very enumeration of the right takes out of the hands of government - even the Third Branch of Government - the power to decide on a case-by-case basis whether the right is really worth insisting upon. A constitutional guarantee subject to future judges' assessments of its usefulness is no constitutional guarantee at all. -- Supreme Court Associate Justice Antonin Scalia, writing for the 5-4 majority in District of Columbia, et al., v. Heller (2008)