Possible Clues:

• ''. . . . . . is its own reward''
• Temperance, for one
• '...... is its own reward''
• ''....is it's own reward'' (6)
• Good trait
• ''...... is its own reward''
• ` `...... is its own reward' '
• ` `..... is its own reward' '
• Good quality; saving grace
• True vice half-destroyed, surprisingly, by its opposite