There is no pillow so soft as a clear conscience.

Related:

• There is no pillow as soft as a clear conscience. -
  French...
• The voice of conscience is so delicate that it is easy to stifle it:
  but it is also so clear that it is impossible to mistake...
• To compare is not to prove.
  French...
• A clear conscience is most often a sign of a bad
  memory...
• Anyone with a clear conscience has a foggy
  memory...
• Gratitude is the heart's memory.
  French...
• There is no flying without wings.
  French...
• There is no such thing as an insignificant enemy.
  French...
• Use soft words and hard arguments. --
  English...