Abandon belief, holding religious teaching to be cowardly (8)
I believe the answer is:
Here is my best explanation:
'be cowardly' is the definition.
('recreant' can be similar in meaning to 'cowardly')
'abandon belief holding religious teaching' is the subsidiary indication.
'abandon belief' becomes 'recant'.
'holding' means one lot of letters goes inside another.
'religious teaching' becomes 're' (religious education).
'recant' going around 're' is 'recreant'.
'to' is the link.
(Other definitions for recreant that I've seen before include "Craven, apostate", "An apostate" and "Cowardly; apostate".)