The call to be a prophet of God came to Isaiah at a time of international crisis in the Middle East. The year that King Uzziah died was 742 B.C. by which time Assyria had embarked on the first moves to control the Middle East. In Israel two coups d'etat since the death of Jeroboam II marked the beginning of the fast decline of the northern kingdom. Uzziah, who had been a leper, was succeeded by his son Jotham who had been co-ruler with his father for a number of years. The writer of the book of Kings says this of Jotham: 'Following the example of his father Uzziah, Jotham did what was pleasing to the LORD. But the pagan places of worship were not destroyed, and the people continued to offer sacrifices and burnt incense there. It was Jotham who built the North Gate of the Temple' (2 Kings 15:34-35). Before the end of Jotham's reign, which was not very long, he was facing political trouble. Syria and Israel began their attempt to force Judah to join with them to resist Assyrian forces. Jotham died before this issue was settled and it was the first crisis which Ahaz, his son, had to face.

This is the background to the call and the first years of the prophetic ministry of Isaiah, and into this situation he took the profound revelation of the absolute goodness, holiness and power of God which came to him when he was in the Temple. This revelation opened his eyes to the evil, unholiness and lack of faith of the people amongst whom he lived and who claimed to be true worshippers of God.

Isaiah became aware that he was just as sinful as the others around him and that between God and man there is a great separation because of man's corruption. The worship that was being offered to God in the Temple was being offered in ignorance of the true character of God. Isaiah was overwhelmed with the realization of the terrifying purity and holiness of God, which judged all that he was, but in the midst of his feeling that he was fit only for destruction, one of the heavenly messengers of the vision brings him purification and forgiveness through burning fire which touches his mouth. The Holy God bridged the great gulf between himself and sinful man through sending the heavenly messenger to Isaiah and cleansing him of his sin. Isaiah's cleansing and forgiveness were immediately followed by his commissioning to go and speak 'for God to the sinful people amongst whom he lived. Isaiah must go and communicate to them what he had learned about God in the vision. That this would be terribly difficult is made clear by the words of verses 9-10. These words are so difficult to understand that commentators provide a number of interpretations of their meaning. They can be understood as irony intended to challenge and shock the hearers into awareness of their sin; they can also mean that the people have gone too far in their sin to repent, or that God will not give them any more time for repentance (as Amos understood in his later visions).

Isaiah's task is to preach to the people, whatever happens. He asks God for how long he is to preach to those who will not hear or understand and the answer is that he must go on until the judgement has fallen on the land (v. 11-13). God's judgement has already been declared on the sin of Judah. This reminds us of what Amos learned about Israel from God in the vision of the crooked wall. But in this message of irrevocable judgement on Judah's sin, there is a ray of hope. The imagery of the stump of the tree that has been cut down refers to the remnant of the people that will survive after the judgement and from whom a new beginning can be made.

We have to see Isaiah's task against the background of the city which was so proud of its heritage as the city of David and the holy city which housed Yahweh's Temple. The people of Jerusalem assumed with self-righteous confidence that they were on very good terms with their God because they lived in the holy city. At the Temple there were daily sacrifices, impressive worship and festivals, in the name of their God. The kings who ruled from Jerusalem were descended from David to whom the promise had been made of a dynasty that would not end, and it was popularly believed that God supported and approved of these kings. The people of Jerusalem could see nothing wrong with themselves and the way they lived; they thought that they were good people, doing what God required of them. Isaiah had to tell them the opposite of this. He had to tell them that they were evil people who were ignorant of what God required of them, and in fact, they did not understand their God at all. Humanly speaking, Isaiah's task was impossible. Only through trusting God completely and obeying God's command to go on speaking until the judgement came, could Isaiah carry out a prophetic ministry in the city of Jerusalem. He had to speak and act for God in faith and obedience, without consideration of any self-interest on his part, or his comfort or safety.

The great difficulty of the task of trying to communicate with those who have shut their ears and eyes to the truth of God, referred to in 6:9-10, is taken up in the four gospels which quote these words in Matthew 13:14-15, Mark 4:12, Luke 8:10 and John 12:40. They are also quoted with reference to Paul's teaching in Acts 28:26-27. Those who are in a state of inner rebellion against God do not want to hear the truth of God because it will demand such a deep change in them and their way of life. God is a threat to them.