"Conscience is the most sacred of all property; other property depending in part on positive law, the exercise of that being a natural and unalienable right. To guard a man's house as his castle, to pay public and enforce private debts with the most exact faith, can give no title to invade a man's conscience, which is more sacred than his castle, or to withhold from it that debt of protection for which the public faith is pledged by the very nature and original conditions of the social pact."