Summon everyone and keep inside church (4,5)
I believe the answer is:
call forth
'summon' is the definition.
(calling forth is a kind of summoning)
'everyone and keep inside church' is the wordplay.
'everyone' becomes 'all' (all people).
'and' says to put letters next to each other.
'keep' becomes 'fort' (I've seen this in other clues).
'inside' is an insertion indicator.
'church' becomes 'ch' (abbreviation on maps etc).
'all'+'fort'='allfort'
'allfort' placed inside 'ch' is 'CALL FORTH'.
(Other definitions for call forth that I've seen before include "Summon" , "Evoke" .)