Don't worry about the interdiction of others and work upon your intentions seriously, there is a reward within it. And what you had in mind before was wrong.
Remarks about the translation
it could also be: Don't bother about forbidding others... but i believe the one up there is the one intended.
the one in Arabic i just cant put my hand on, preventing means stopping others from doing something, this one is like: ordering others not to do something, what is the right word fot that?
hi Kafetzou, i believe the English one can be tweaked a bit further, may be it should be:
"...And what you had in mind before 'was' wrong."
and one more thing: im not sure about "a reward" it makes it sound like a single reward, but I am referring to the kind of spiritual reward, that cannot be counted... not sure though!