The holy father came in with the prior (8)
I believe the answer is:
previous
'the prior' is the definition.
(thesaurus)
'the holy father came in' is the wordplay.
'the holy' becomes 'pious'.
'father' becomes 'rev' (I've seen this in other clues).
'came in' means one lot of letters goes inside another.
'pious' placed around 'rev' is 'PREVIOUS'.
'with' is the link.
(Other definitions for previous that I've seen before include "earlier convictions" , "Foregoing" , "Earlier, occasion say" , "Overhasty; existing earlier" , "form" .)