Well, if it's "His will," they why aren't they already saved? Obviously, they have to DO something with "His will." Likewise with health, prosperity, fear, it is NOT "His will" that people are sick, defeated (question, was Jesus EVER, EVER physically ill? Anyone? Anyone? Bueller? Bueller?). But God will LET you do drugs, He will LET you join with prostitutes, He will LET you fly planes into towers. But that isn't His will.
My favorite verse for those who think that God can do anything in this earth just because He is God is where Jesus goes to Nazareth to work miracles, but "there, He could do no mighty works, save heal a few sick people" because of their "unbelief." So apparently their unbelief had something to do with the SON OF GOD not being able to do a MIRACLE!