It was under circumstances of difficulty and discouragement that Isaiah, while yet a young man, was called to the prophetic mission. Disaster was threatening his country. By their transgression of God's law the people of Judah had forfeited His protection, and the Assyrian forces were about to come against the kingdom of Judah. But the danger from their enemies was not the greatest trouble. It was the perversity of the people that brought upon the Lord's servant the deepest depression. By their apostasy and rebellion they were inviting the judgments of God. The youthful prophet had been called to bear to them a message of warning, and he knew that he would meet with obstinate resistance. He trembled as he viewed himself and thought of the stubbornness and unbelief of the people for whom he was to labor. His task seemed to him almost hopeless. Should he in despair relinquish his mission and leave Israel undisturbed to their idolatry? Were the gods of Nineveh to rule the earth in defiance of the God of heaven? 2TT 348.1
Such thoughts as these were crowding upon his mind as he stood under the portico of the holy temple. Suddenly the gate and the inner veil of the temple seemed to be uplifted or withdrawn, and he was permitted to gaze within, upon the holy of holies, where even the prophet's feet might not enter. There rose up before him a vision of Jehovah sitting upon a throne high and lifted up, while His train filled the temple. On each side the throne hovered the seraphim, two wings bearing them up, two veiling their faces in adoration, and two covering their feet. These angel ministers lifted up their voices in solemn invocation, “Holy, holy, holy, is the Lord of hosts: the whole earth is full of His glory,” until post and pillar and cedar gate seemed to tremble at the sound, and the house was filled with their praise. 2TT 348.2
Never before had Isaiah realized so fully the greatness of Jehovah or His perfect holiness; and he felt that in his human frailty and unworthiness he must perish in that divine presence. “Woe is me!” he cried; “for I am undone; because I am a man of unclean lips, and I dwell in the midst of a people of unclean lips: for mine eyes have seen the King, the Lord of hosts.” Isaiah 6:3, 5. But a seraph came to him to fit him for his great mission. A living coal from the altar was laid upon his lips with the words: “Lo, this hath touched thy lips; and thine iniquity is taken away, and thy sin purged.” And when the voice of God was heard saying, “Whom shall I send and who will go for us?” Isaiah with holy confidence responded, “Here am I; send me.” Verses 7, 8. 2TT 349.1
What though earthly powers should be arrayed against Judah? What though Isaiah should meet with opposition and resistance in his mission? He had seen the King, the Lord of hosts; he had heard the song of the seraphim, “The whole earth is full of His glory;” and the prophet was nerved for the work before him. The memory of this vision was carried with him throughout his long and arduous mission. 2TT 349.2