Isaiah's ministry lasted approximately half a century, continuing through the reigns of Jotham, Ahaz, and Hezekiah. Tradition tells us that he suffered a martyr's death during the reign of King Manasseh. His work brought him into direct contact with kings and priests, and he encountered strong opposition from both groups. At times, this opposition was so strong that he was forced to give up speaking in public and confine his ministry to a group of disciples with whom he met privately. With regard to the priests and the services that they performed, Isaiah expressed convictions that were similar to those spoken to the people of Israel by Amos and Hosea. For example, speaking for Yahweh, he says, "'The multitude of your sacrifices — what are they to me?' says the Lord." And again, "Your New Moon festivals and your appointed feasts my soul hates." He even insists that Yahweh will not listen to the multitude's prayers: "When you spread out your hands in prayer, I will hide my eyes from you; even if you offer many prayers, I will not listen. Your hands are full of blood."
In the same spirit, Isaiah criticizes the economic policies that were not only sanctioned but encouraged by the rulers of the land. In "The Song of the Vineyard," which was probably chanted by the prophet, we find these words: "Woe to you who add house to house and join field to field till no place is left and you live alone in the land." This chant protests the way in which the poor people were deprived of their property in order to satisfy the claims of their creditors, who had taken unfair advantages of these people's unfortunate circumstances in order to enrich themselves.
The prophet's criticism of kings was expressed on many occasions, but never was it more pronounced than when he protested against the foreign alliances that were being negotiated. Early in Isaiah's ministry, he warned King Ahaz against the dangers involved in an alliance with Assyria. The heads of two puppet kingdoms that were all that remained of northern Israel asked King Ahaz to join with them in a coalition against Assyria. When Ahaz refused, they threatened to make war against him. Ahaz was frightened and wanted to appeal to Assyria for help. Isaiah clearly saw the folly that would be involved in a move of this kind, and in a prophecy that has often been misinterpreted as a reference to a coming Messiah, he warned King Ahaz that within three or four years those two puppet kingdoms that he feared would be completely routed. On the other hand, if Ahaz wanted to protect Judah, he should give his attention to those conditions that needed moral reform. King Ahaz did not heed Isaiah's advice. He went ahead with his plans, and as a result, Judah was placed in a subservient relation to the Assyrian empire.
