What were the roles of the hebrew prophets?

Answer 1

The main role was to exhort the people to higher standards in serving God. The prophets spoke of God and His will, and stridently pointed out any and all of the people's faults, holding them up to the spotlight. This is why the people seem to be such sinners in the words of the prophets, even though they were, generally speaking, on a higher spiritual level than any later generation (Talmud, Yoma 9b).

Other roles which the prophets fulfilled were to predict events (especially the Destruction, as a call to repentance); and to comfort the people with the prophecies of the eventual redemption. They also offered inspired counsel; and the kings sometimes sought their instruction in national matters. After the monarchy ceased, prophecy soon stopped.

Each of the prophets was a Torah-leader and teacher, and they had many disciples.