Clue: St Francis's body beginning to strengthen after long periods on soup (7,3)
Answer: BROTHER ASS
Explanation: Definition: St Francis's body
**S**(trengthen) after **ERAS** ("long periods") on **BROTH** ("soup"), so **BROTH-ERAS-S** 
*Apparently, Francis of Assisi used to refer to his body as Brother Ass.