The spiritual guidance of the Jewish people after the delivery of the Law by Moses was placed in the hands of the priesthood.
The priests in addition to their ministrations in holy things, they were also the teachers of the people, interpreters of the Law, and the medium of communication between the nation and God. The gradual degeneracy of the Priesthood - culminating in the wickedness of Eli's sons and their rejection, paved the way for the introduction of the Prophets.
Samuel was the first of the Prophets. Thenceforward the order played an important part in the history of the nation. The "Schools of the Prophets," founded by Samuel, continued until the time of the Captivity to Babylon and furnished an ample supply of religious teachers and guides. They instructed the people in their moral duties, setting before them their obligations to the covenant, and pointing them in the right way with regards to the ordinary relations of life.
From amongst these were ordinarily taken the prophets who were more directly inspired with the Spirit of God to declare His way to the people. They acted independently of the political leaders and very often in antagonism to them - more especially during the period after Solomon's reign, when kings and people alike (with few exceptions) fell away from the worship of God into degrading idolatry.
As well as being made the bearers of the Divine warnings and reproofs and judgments, some of them, gifted with a more clear perception of God's will and purpose and speaking "as they were moved by the Holy Ghost" kept alive the promise of the Messiah and pointed forward to His coming. Of such were the number whose writings are recorded in the Holy Scriptures and who have preserved to later ages an authentic and inspired record of the events of their respective periods. Through this, we can clearly trace the progress of the purpose of God marching steadily on to its fulfilment.
The "writing" prophets are divided into two groups, each of which is arranged in chronological order and distinguished as the "greater" and "minor" prophets. The first group consists of Isaiah, Jeremiah (including Lamentations), Ezekiel, and Daniel. The second group extends from Hosea to Malachi.