Work on church twice as quickly (4-4)
I believe the answer is:
chop-chop
'quickly' is the definition.
('chop-chop' can be a synonym of 'quickly')
'work on church twice' is the subsidiary indication.
'work' becomes 'op' (common abbreviation for 'opus').
'on' says to put letters next to each other.
'church' becomes 'ch' (common abbreviation).
'twice' says to double the letters.
'op' put after 'ch' is 'chop'.
'chop' doubled is 'chopchop'.
'as' is the link.
(Other definitions for chop-chop that I've seen before include "Get a move on!" , "Hurry up!" , "Quickly!" .)