The burden we bear (4)
I believe the answer is:
onus
I believe this clue is a double definition.
'the burden' is the first definition.
('onus' can be a synonym of 'burden')
'we bear' is the second definition.
(we carry anything on us)
(Other definitions for onus that I've seen before include "Burden, duty" , "'Burden, load (4)'" , "Duty or responsibility" , "'Burden, of proof (4)'" , "Obligation - charge" .)