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,