It precedes Mass for verger (6)
I believe the answer is:
sexton
'verger' is the definition.
(thesaurus)
'it precedes mass' is the wordplay.
'it' becomes 'sex' (I can't justify this - if you can you should give a lot more credence to this answer).
'precedes' says to put letters next to each other (some letters come before others).
'mass' becomes 'ton'.
'sex'+'ton'='SEXTON'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for sexton that I've seen before include "church assistant" , "parish factotum" , "Church functionary" , "Graveyard employee" , "Person who tends a church and churchyard" .)