Wordnet 3.0
NOUN (2)
1. 
 (Christian theology) a state of sanctification by God; 
 the state of one who is under such divine influence; 
- Example: "the conception of grace developed alongside the conception of sin"- Example: "it was debated whether saving grace could be obtained outside the membership of the church"- Example: "the Virgin lived in a state of grace"[syn: grace, saving grace, state of grace]
2.  a redeeming quality or characteristic; 
- Example: "her love of music remains her one saving grace"
- Example: "her sense of humor has to be a saving grace"
- Example: "the saving grace for both developments is that they are creating jobs"
WordNet (r) 3.0 (2006):
saving grace
    n 1: (Christian theology) a state of sanctification by God; the
         state of one who is under such divine influence; "the
         conception of grace developed alongside the conception of
         sin"; "it was debated whether saving grace could be
         obtained outside the membership of the church"; "the Virgin
         lived in a state of grace" [syn: grace, saving grace,
         state of grace]
    2: a redeeming quality or characteristic; "her love of music
       remains her one saving grace"; "her sense of humor has to be
       a saving grace"; "the saving grace for both developments is
       that they are creating jobs"