Money leant to a friend must be recovered from an enemy.

Related:

• The enemy of my enemy is my friend
  Arab...
• Reconciled friend is a double
  enemy. --...
• An open enemy is better than a false friend.
  Greek...
• Tell nothing to thy friend that thy enemy may not know.
  Danish...
• One enemy can harm you more than a hundred friends can do you good.
  German...
• If you would keep a secret from an enemy,
  tell it not to a friend...
• He who would rule must hear and be deaf, see and be blind.
  German...