Religious traveller embedding stone in a staff (7)
I believe the answer is:
apostle
'religious traveller' is the definition.
(the Apostles travelled to spread Jesus' teachings)
'stone in a staff' is the wordplay.
'stone' becomes 'st'.
'in' indicates putting letters inside.
'staff' becomes 'pole' (I've seen this before).
'a'+'pole'='apole'
'st' placed inside 'apole' is 'APOSTLE'.
'embedding' acts as a link.
This may not be correct. It may be part of another bit of the clue.
(Other definitions for apostle that I've seen before include "Originally, one sent to preach the gospel" , "Good man" , "Preacher perhaps" , "Ardent espouser of new system" , "John, perhaps" .)