To give a saint help, you need to be sober (5)
I believe the answer is:
staid
'to be sober' is the definition.
(synonyms)
'to give a saint help' is the wordplay.
'to give' is a charade indicator (letters next to each other).
'a saint' becomes 'st' (abbreviation).
'help' becomes 'aid' (synonyms).
'st' put next to 'aid' is 'STAID'.
'you need' is the link.
(Other definitions for staid that I've seen before include "Very conventional and dull" , "Sedate and serious" , "Serious or sober in character" , "Unadventurous, dull" , "Conventional (character)" .)