The conflict between morality and desire

In a message to the International Stoic Forum Grant Sterling provided the reason why we should eliminate all desires for externals.

John: How do we know when something is appropriate for the will and when something is better left alone?

Grant: This is a general problem, which would require a very long answer
to discuss adequately. Becker (in _A New Stoicism_) regards stoicism
and intuitionism as fundamentally opposed. I think quite the opposite--
they are answering different questions in a compatible way. Both systems
generally present the idea that what we ought to do in a situation is
fairly obvious the vast majority of the time, and only in those rare
occasions when we have conflicting duties is the case difficult.
In other words, I think [that] it is very rare when we really are
in a situation where we don't know what's appropriate to do--the
fundamental moral conflict is not between different ideas of what is
morally appropriate. The conflict is between morality and desire--we
see what we ought to do, but it conflicts with what we desire to do.
If we have banished desire, then we will no longer have much difficulty
in knowing what is appropriate and doing it, which is why stoic
teaching on the connection between desire and happiness is
compatible with stoic teaching on virtue.