The word ‘apostle’ simply means a messenger. Sometimes Scripture uses the term of those who were not in the special circle of the Twelve, and it uses the term in its literal sense, a messenger, an evangelist; we don’t use it, or we shouldn’t use it that way today, to avoid confusion.
It is an astonishing thing today, that many people who say they are born again do not seem to be set apart. They carry on as though they were in the world in every way and they behave just like worldlings. There are even churches and the whole church behaves as though it is some institution which belongs to this world. We are set apart for him. Even if we are scorned, even if we are derided, we are set apart for him.