Sacred text used as an incantation (6)
I believe the answer is:
mantra
I believe this clue is a double definition.
'sacred text' is the first definition.
(mantra is a kind of sacred text)
'an incantation' is the second definition.
(I've seen this before)
'used as' acts as a link.
(Other definitions for mantra that I've seen before include "Oft-repeated slogan or phrase" , "Incantation, Hindu psalm" , "Words repeated as an aid to meditation" , "oft repeated stock phrase?" , "Sacred word for repetition" .)