St Paul himself knew when he was speaking by the Spirit, and when he was not; and we too can recognize to some extent when the afflatus comes upon him.
In natural soothsaying this frenzy is the necessary physical accompaniment of an afflatus which, though it seems supernatural to a rude people, is really akin to poetic inspiration.
So far was the afflatus of the Spirit from being conditioned by the rite, that in Acts x.
As no one could curse Jesus except under the influence of a devilish afflatus, so none could say "Jesus is Lord" except he was inspired by the Holy Spirit.
It does not, of course, follow that everyone who had shared in the divine afflatus of prophetic enthusiasm gave forth oracles; but the prophets as a class stood nearer than other men to the mysterious workings of Yahweh, and it was in their circle that revelation seemed to have its natural home.