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.
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.
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.
With the prophets it is quite otherwise; they appear not individually but in bands; their prophesying is a united exercise accompanied by music, and seemingly dance-music; it is marked by strong excitement, which sometimes acts contagiously, and may be so powerful that he who is seized by it is unable to stand, 2 and, though this condition is regarded as produced by a divine afflatus, it is matter of ironical comment when a prominent man like Saul is found to be thus affected.
More than this hardly lies in the expression "a divine spirit" (a'r5K min), which is used not only of the prophetic afflatus but of the evil frenzy that afflicted Saul's later days.