Among the people of God of the Old Covenant who were actively engaged in His ministry were not only the priests, who were chiefly in charge of public worship, although they also did some teaching, but also the prophets, the official spokesmen of God to the children of Israel and others, whose work consisted not only in foretelling future events, but, in general, in uttering the message of God entrusted to them, whether this pertained to an exposition of the will of God, to an application of the Law to the circumstances of their time, or to an unveiling of the future, particularly of the glories of the Messianic period. The prophets were also called seers, men of God, messengers of Jehovah, servants of the Lord, in short, organs and instruments of the Lord in making Himself, His person and His will, known to men. They performed their work either in prophetical speech, spoken or written, or by the narration of visions and dreams vouchsafed to them by the Lord, or by symbolical acts signifying certain events in the coming history of God's people.
Among the men whose prophetical writings have been preserved in the canon of the Bible, Isaiah, the son of Amoz, stands first. Of the circumstances of his life little is known. He seems to have descended from a noble family, according to Jewish tradition a side-line of the reigning family of David. Isaiah was married and lived in Jerusalem, his two sons, by God's command, bearing names with symbolical meanings. He began his activity as prophet in the year in which King Uzziah died, 758 B. C. and appears to have been active for some sixty years. Beside his book of prophecy Isaiah also wrote a historical work, 2Ch_26:22. According to an ancient tradition, which, however, cannot be verified, Isaiah suffered martyrdom under King Manasseh.
The period of Isaiah's activity is that of the Kings Uzziah, Jotham, Ahaz, and Hezekiah. In the first part of this period the kingdom of Judah was in a most flourishing condition, 2Ki_14:21, At this time the double kingdom once more had the extent which it had possessed in the days of David and Solomon. But with the accession of Ahaz came a period of disintegration and decay: gross idolatry, human sacrifices, desecration of the Temple, turning to the Assyrians for help, who, in turn, became a scourge of the country. With the accession of Hezekiah things took a turn for the better, since he restored the Temple services, celebrated the Passover, renounced the covenant with the Assyrians, and was miraculously delivered from the power of the Assyrian king. But when he gave himself to pride and made overtures to the Babylonians, he paved the way for the later ascendency of this world power and for the fall of the southern kingdom.
Isaiah stands midway between Moses and Christ. He was, at the same time, the great preacher of repentance and the evangelist of the Old Testament. To the godless he proclaimed the wrath of the Lord, the inevitable destruction, with an earnestness and impressiveness which is overwhelming in its force; to the believers, the small remnant, he preaches the comforting message of the deliverance of mankind through the Messiah, the Servant of Jehovah.
The Book of Isaiah is clearly divided into two parts 1 to 39 and 40 to 66, both parts being grouped about certain historical facts, the first being the hypocritical apostasy of Ahaz and the subsequent invasion of Sennacherib, the second the foolish act of Hezekiah in showing the envoys of the Babylonian king the treasures of his house and thus inviting the world power to covet the riches of Judah. The first group of prophecies concerns not only Judah and Jerusalem, but also the chief foreign countries and nations, chiefly Assyria, Babylon, Moab, Syria, Egypt, and Tyre. The second group is known as the Book of Consolations and pictures the restoration of the remnant of Israel, the Messianic King, and the final glory of the Church.