Calvinist John Piper explains that all things happen not by “mere permission”:
3) Does God Permit Sin?
Consider now the term permits. This is the preferred term in Arminian theology, in which it amounts to a denial that God causes sin. For the Arminian, God does not cause sin; he only permits it. Reformed theologians, however, have also used the term, referring to God’s relation to sin. The Reformed, however, insist contrary to the Arminians that God’s “permission” of sin is no less efficacious than his ordination of good. Calvin denies that there is any “mere permission” in God:
From this it is easy to conclude how foolish and frail is the support of divine justice afforded by the suggestion that evils come to be not by [God’s] will, but merely by his permission. Of course, so far as they are evils, which men perpetrate with their evil mind, as I shall show in greater detail shortly, I admit that they are not pleasing to God. But it is a quite frivolous refuge to say that God otiosely [= idly] permits them, when Scripture shows Him not only willing but the author of them.1
God’s “permission” is an efficacious permission. . . .