Prophetic means predictive. Only god, provided the [and not an] IT exists, can tell us what will happen and why IT is making happen what we will see or experience happen.
Isaiah was called and deemed by the ancient priestly class a prophet. Isaiah, reportedly, was a predictor and a teacher.
If Isaiah indeed was taken as; or in fact is/was a teacher and a seer; then, he sucked that god-like knowledge out of his thumb. So, god just looked on but did not interfere in Isaiah’s thinking or discovering the ‘truth’.
If you know what “truth to power” means/entails to do and you also know it [seen, experienced it], then, i am totally lost as to what to say or think of it.
In any case, if Yahweh, God, or Jesusgod exist; then, only they or one of them only is a Teacher [Mt 23:8]. NT also teaches not to go beyond what is written. This means that no one should interpret what Bible says.
This pertains also to “truth to power”. Truth to power remains forever truth to power.
Paul said that, i suggest, because he expected that the interpretations of Bible what would cause fissures, acrimony, accusations, anger, etc, in Jesus’ church.