What this passage, attributed to Patrick Henry (though there is serious doubt as to whether these are the actual words he spoke), means is that Henry would prefer to die rather than to live without liberrty.
To understand the meaning of the passage you give, you must first understand what Henry wants God to "forbid." What he is saying is that he wants God to forbid that he and others would rather have peaceful lives without liberty. He asks
Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery?
Henry then goes on to speak the lines you cite. He is essentially saying that other people might be okay with a peaceful life without liberty, but he himself would not be. If he cannot be free, he would rather die.