One fetching and carrying timber from the ark (6)
I believe the answer is:
gopher
I believe this is a double definition.
'one fetching and carrying' is the first definition.
(a gopher or gofer fetches things)
'timber from the ark' is the second definition.
(Noah's ark was made from gopher wood)
(Other definitions for gopher that I've seen before include "biblical wood" , "American burrowing rodent or ground squirrel" , "Burrowing US rodent" , "skilled digger" , "Burrowing rodent of north and central America" .)