Determination found in Christe eleison (5)
I believe the answer is:
steel
'determination' is the definition.
(steel can figuratively mean determination)
'in christe eleison' is the wordplay.
'in' says the answer is hidden in the clue.
'STEEL' is hidden in the letters of 'christe eleison'.
'found' is the link.
(Other definitions for steel that I've seen before include "Structural metal alloy" , "Strong metal" , "Determination, metal" , "Mixture of carbon and iron" , "Iron/carbon alloy" .)