Call to mind first half of authentic prayer
I believe the answer is:
recollect
'call to mind' is the definition.
(I've seen this before)
'first half of authentic prayer' is the wordplay.
'first half of' indicates taking half.
'authentic' becomes 'real' (I've seen this before).
'prayer' becomes 'collect' (collect is a type of prayer).
'real' cut in half is 're'.
're'+'collect'='RECOLLECT'
(Other definitions for recollect that I've seen before include "Look back on" , "Call to mind" , "Bring back to mind." , "Remember" , "Flock together again" .)