The calls of Jeremiah and Ezekiel are recounted in the opening chapters of the books that bear their names. Isaiah’s call vision only appears in chapter 6. Many scholars, however, think that it originally introduced an “Isaiah memoir” which included at least chapters 7 and 8, although chapter 7 is narrated in the third person.
The opening statement of Isaiah 6 is startling: “I saw the Lord.” According to one strand of biblical tradition, human beings could not see God and live. Even Moses was not allowed to see God’s face (Exod 33:20, despite the statement in Exod 33:11 that the Lord used to speak to Moses face to face). There was another tradition, however, in which prophets could claim unequivocally that they saw the Lord. (See the story of Micaiah ben Imlah in 1 Kings 22; Ezekiel has a rather blurry vision of “the appearance of the likeness of the glory of the Lord,” Ezek 1:28). Both Micaiah and Isaiah see the Lord as a majestic figure sitting on a throne. In Isaiah’s case, the throne is in the temple. The Lord is surrounded by seraphim, which are fiery creatures, apparently a kind of flying serpent (compare Isa 14:29; 30:6; Num 21:6-9). In ancient Near Eastern art, winged creatures with bodies in animal or human form often appear as guardians in palaces and temples. Here, however, the seraphim have a benign function: they proclaim the holiness of God. God is often called “the holy one of Israel” in the book of Isaiah.
Seeing the Lord, however, is not without its problems, even for a prophet. Holiness is a condition of great purity, associated with a spiritual condition, in contrast to the corruption of flesh. (The contrast between spirit and flesh will appear again later in the book). Confronted with the holiness of God, Isaiah realizes that he is man of unclean lips and lives among a people of unclean lips. To stand in the presence of the Lord, he must be purified. One the seraphs purifies him by touching his lips with a burning coal. We must assume that this happens in the prophet’s imagination, not physically. The implication is that the human condition can only be purified by the radical and painful process of burning. This will have implications for the fate of the people of Judah.
The purpose of Isaiah’s vision, however, is not his own purification. The Lord is apparently surrounded by his divine council, consisting of spirits (often called angels in modern parlance). He asks for a volunteer to proclaim a message to Judah. (Compare the story of Micaiah ben Imlah in 1 Kings 22, where the Lord asks for a volunteer to deceive King Ahab). Isaiah volunteers. He is given a strange message to deliver. He is to make the mind of the people dull so that they cannot comprehend. Compare the story of the Exodus, where the Lord hardens Pharaoh’s heart (Exod 7:3; 9:12). Isaiah’s mission to warn the people would fail, but it was supposed to fail. Judah is being set up for punishment. Usually, we think of the prophets as trying to get the people to repent. This is clearly the case in the Book of Jeremiah. Sometimes, however, they are simply proclaiming what the Lord is going to do. Ezekiel compares the prophet to a watchman (Ezek 3:17). The watchman’s job is to give a warning. Whether the people heed the warning is not his responsibility. This also seems to be the case in Isaiah 6.
How long will the people fail to comprehend? Until they have suffered destruction: until cities lie waste and the land is utterly desolate, and the Lord sends people far away. This is a reference to the Assyrian practice of deporting conquered people, to break their ability to resist. This happened to the northern kingdom of Israel in Isaiah’s lifetime. It did not happen to Judah, although it would happen later, at the hands of the Babylonians. The most severe destruction of Judah in the Assyrian era would happen late in Isaiah’s career when Sennacherib ravaged the country, but did not capture Jerusalem. There is a reference to that episode in Isa 1:8: “daughter Zion is left like a booth in a vineyard.” The fact that Jerusalem survived on that occasion would strengthen the belief that God would always leave a remnant. Isaiah had already affirmed that a remnant would survive early in his career, by naming his son Shear-yashuv, a remnant will return (Isa 7:3)
In Isaiah 6, however, the emphasis is on destruction: “If a tenth part remain in it, it will be burned again, like a terebinth or oak, whose stump remains standing when it is felled” (6:13). The last line of the chapter is a gloss by a scribe: “the holy seed is its stump.” Even though Judah would be reduced to a stump in Isaiah’s lifetime, a remnant would remain.