WE may deal with this text as falling into three parts: the vision, its effect on the prophet, and his commission.
I. The Vision. -- 'In the year that King Uzziah died' is more than a date for chronological accuracy. It tells not only when, but why, the vision was given. The throne of David was empty.
God never empties places in our homes and hearts, or in the nation or the Church, without being ready to fill them. He sometimes empties them that He may fill them. Sorrow and loss are meant to prepare us for the vision of God, and their effect should be to purge the inward eye, that it may see Him. When the leaves drop from the forest trees we can see the blue sky which their dense abundance hid. Well for us if the passing of all that can pass drives us to Him who cannot pass, if the unchanging God stands out more clear, more near, more dear, because of change.
As to the substance of this vision, we need not discuss whether, if we had been there, we should have seen anything. It was doubtless related to Isaiah's thoughts, for God does not send visions which have no point of contact in the recipient. However communicated, it was a divine communication, and a temporary unveiling of an eternal reality. The form was transient, but Isaiah then saw for a moment 'the things which are' and always are.
The essential point of the vision is the revelation of Jehovah as king of Judah. That relation guaranteed defence and demanded obedience. It was a sure basis of hope, but also a stringent motive to loyalty, and it had its side of terror as well as of joyfulness. 'You only have I known of all the families of the earth: therefore I will punish you for all your iniquities.' The place of vision is the heavenly sanctuary of which the temple was a prophecy. Eminently significant and characteristic of the whole genius of the Old Testament is the absence of any description of the divine appearance. The prophet saw things 'which it is not lawful for a man to utter,' and his silence is not only reverent, but more eloquent than any attempt to put the Ineffable into words. Even in this act of manifestation God was veiled, and 'there was the hiding of His power.' The train of His robe can be spoken of, but not the form which it concealed even in revealing it. Nature is the robe of God. It hides while it discloses, and discloses while it hides.
The hovering seraphim were in the attitude of service. They are probably represented as fiery forms, but are spoken of nowhere else in Scripture. The significance of their attitude has been well given by Jewish commentators, who say, 'with two he covered his face that he might not see, and with two he covered his body that he might not be seen' and we may add, 'with two he stood ready for service, by flight whithersoever the King would send.' Such awe-stricken reverence, such humble hiding of self, such alacrity for swift obedience, such flaming ardours of love and devotion, should be ours. Their song celebrated the holiness and the glory of Jehovah of hosts. We must ever remember that the root-meaning of 'holiness' is separation, and that the popular meaning of moral purity is secondary and derivative. What is rapturously sung in the threefold invocation of the seraphs is the infinite exaltation of Jehovah above all creatural conditions, limitations, and, we may add, conceptions. That separation, of course, includes purity, as may be seen from the immediate effect of the vision on the prophet, but the conception is much wider than that. Very beautifully does the second line of the song re-knit the connection between Jehovah and this world, so far beneath Him, which the burst of praise of His holiness seems to sever. The high heaven is a bending arch; its inaccessible heights ray down sunshine and drop down rain, and, as in the physical world, every plant grows by Heaven's gift, so in the world of humanity all wisdom, goodness, and joy are from the Father of lights. God's 'glory' is the flashing lustre of His manifested holiness, which fills the earth as the train of the robe filled the temple. The vibrations of that mighty hymn shook the 'foundations of the threshold' (Rev. Ver.) with its thunderous harmonies. 'The house was filled with smoke' which, since it was an effect of the seraph's praise, is best explained as referring to the fragrant smoke of incense which, as we know, symbolised 'the prayers of saints.'
II. The effect of the vision on the prophet. -- The vision kindled as with a flash Isaiah's consciousness of sin. He expressed it in regard to his words rather than his works, partly because in one aspect speech is even more accurately than act a cast, as it were, of character, and partly because he could not but feel the difference between the mighty music that burst from these pure and burning lips and the words that flowed from and soiled his own. Not only the consciousness of sin, but the dread of personal evil consequences from the vision of the holy God, oppressed his heart. We see ourselves when we see God. Once flash on a heart the thought of God's holiness, and, like an electric search- light, it discloses flaws which pass unnoticed in dimmer light. The easy-going Christianity, which is the apology for religion with so many of us, has no deep sense of sin, because it has no clear vision of God. 'I have heard of Thee by the hearing of the ear; but now mine eye seeth Thee: wherefore I abhor myself, and repent in dust and ashes.'
The next stage in Isaiah's experience is that sin recognised and confessed is burned away. Cleansing rather than forgiveness is here emphasised. The latter is, of course, included, but the main point is the removal of impurity. It is mediated by one of the seraphim, who is the messenger of God, which is just a symbolical way of saying that God makes penitents 'partakers of His holiness,' and that nothing less than a divine communication will make cleansing possible. It is effected by a live coal. Fire is purifying, and the New Testament has taught us that the true cleansing fire is that of the Holy Spirit. But that live coal was taken from the altar. The atoning sacrifice has been offered there, and our cleansing depends on the efficacy of that sacrifice being applied to us.
The third stage in the prophet's experience is the readiness for service which springs up in his purged heart. God seeks for volunteers. There are no pressed men in His army. The previous experiences made Isaiah quick to hear God's call, and willing to respond to it by personal consecration. Take the motive-power of redemption from sin out of Christianity, and you break its mainspring, so that the clock will only tick when it is shaken. It is the Christ who died for our sins to whom men say, 'Command what Thou wilt, and I obey.'
III. The prophet's commission. -- He was not sent on his work with any illusions as to its success, but, on the contrary, he had a clear premonition that its effect would be to deepen the spiritual deafness and blindness of the nation. We must remember that in Scripture the certain effect of divine acts is uniformly regarded as a divine design. Israel was so sunk in spiritual deadness that the issue of the prophet's work would only be to immerse the mass of 'this people' farther in it. To some more susceptible souls his message would be a true divine voice, rousing them like a trumpet, and that effect was what God desired; but to the greater number it would deepen their torpor and increase their condemnation. If men love darkness rather than light, the coming of the light works only judgment.
Isaiah recoils from the dreary prospect, and feels that this dreadful hardening cannot be God's ultimate purpose for the nation. So he humbly and wistfully asks how long it is to last. The answer is twofold, heavy with a weight of apparently utter ruin in its first part, but disclosing a faint, far-off gleam of hope on its second. Complete destruction, and the casting of Israel out from the land, are to come. But as, though a goodly tree is felled, a stump remains which has vital force (or substance) in it, so, even in the utmost apparent desperateness of Israel's state, there will be in it 'the holy seed,' the 'remnant,' the true Israel, from which again the life shall spring, and stem and branches and waving foliage once more grow up.