Calls to give up immorality (5,2)
I believe the answer is:
drops in
'calls' is the definition.
(dropping in is a kind of calling)
'give up immorality' is the wordplay.
'give up' becomes 'drop' (dropping is a kind of giving up).
'immorality' becomes 'sin' (sin is a kind of immorality).
'drop'+'sin'='DROPS IN'
'to' is the link.
(Other definitions for drops in that I've seen before include "eye thus getting less inflamed?" , "Comes to see" , "Casually visits" , "Calls casually" .)