How we cite our quotes: (Page.Paragraph)
Quote #4
The hero to whom such a helper appears is typically one who has responded to the call. The call, in fact, was the first announcement of the approach of this initiatory priest. But even to those who apparently have hardened their hearts the supernatural guardian may appear; for, as we have seen: "Well able is Allah to save." (67.1)
Here's that balance again: destiny is going to be served no matter what, but the hero's choices can make the path smoother and easier.
Quote #5
To move toward destiny is like eternity. To know eternity is enlightenment, and not to recognize eternity brings disorder and evil. (175.2)
The whole point of the Hero's Journey is to put the hero's free will in sync with the universe, and thus enjoy the enlightenment it brings. It's not supposed to be a struggle between man and fate, but a way of putting man on the same page as fate.
Quote #6
The irony, of course, lies in the fact that, whereas the hero who has won the favor of the god may beg for the boon of perfect illumination, what he generally seeks are longer years to live, weapons with which to slay his neighbor, or the health of his child. (175.5)
Another case where the hero gets to exercise free will…but note Campbell's tone: choosing poorly means staying mired in petty concerns instead of embracing destiny. That always brings pain.