It is by the goodness of God that we have in our country three unspeakably precious things: freedom of speech, freedom of conscience, and the prudence never to practice either.
Hello! Could someone else interpret the sentence which I highlight in blue for me? Thanks in advance!
It's obviously a very silly aphorism; some other context would be necessary to explain why he said it. For example, he might have just been heavily criticised for speaking out about something.