One with faith is tense on a job (6)
I believe the answer is:
theist
'one with faith' is the definition.
(someone who believes in God)
'tense on a job' is the wordplay.
'tense' becomes 't' (abbreviation used in many dictionaries).
'on' says to put letters next to each other.
'a job' becomes 'heist' (job can mean a robbery or heist).
't'+'heist'='THEIST'
'is' acts as a link.
(Other definitions for theist that I've seen before include "Tithes for believer in God" , "Person in good faith" , "Tithes (anag.)" , "Person who believes in the existence of a god" , "Believer in a god or gods" .)