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.
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.
In the conversation with Nicodemus we seem to overhear a protest against the growing tendency of the last years of the 1st century to substitute formal sacraments for the free afflatus of the spirit, and to "crib, cabin and confine" the gift of prophecy.
Whatever happened to passion and vision and the divine afflatus in poetry?