Send drink outside for messenger (7)
I believe the answer is:
apostle
'for messenger' is the definition.
(the apostles spread Jesus' message)
'send drink outside' is the wordplay.
'send' becomes 'post' (to send in the post).
'drink' becomes 'ale' (type of beer).
'outside' is an insertion indicator (some letters go outside others).
'post' going inside 'ale' is 'APOSTLE'.
(Other definitions for apostle that I've seen before include "Missionary or evangelist" , "Disciple of Jesus Christ" , "A follower of Jesus" , "Leaps to find teacher of faith" , "Holy person" .)