And one called to another and said: “Holy, holy, holy is the LORD of hosts; the whole earth is full of his glory!” (Isa 6:3, ESV)

As the prophet Isaiah beheld the glory of the Lord, he was amazed, and, overwhelmed with a sense of his own weakness and unworthiness, he cried, “Woe is me! 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.” {4BC 1138.6}
Isaiah had denounced the sin of others; but now he sees himself exposed to the same condemnation he had pronounced upon them. He had been satisfied with a cold, lifeless ceremony in his worship of God. He had not known this until the vision was given him of the Lord. How little now appeared his wisdom and talents as he looked upon the sacredness and majesty of the sanctuary. How unworthy he was! how unfitted for sacred service! His view of himself might be expressed in the language of the apostle Paul, “O wretched man that I am! who shall deliver me from the body of this death?” {4BC 1139.1}
But relief was sent to Isaiah in his distress.
Then one of the seraphim flew to me, having in his hand a burning coal that he had taken with tongs from the altar. And he touched my mouth and said: “Behold, this has touched your lips; your guilt is taken away, and your sin atoned for.” (Isa 6:6-7)
The vision given to Isaiah represents the condition of God’s people in the last days. They are privileged to see by faith the work that is going forward in the heavenly sanctuary. “And the temple of God was opened in heaven, and there was seen in his temple the ark of his testament.” As they look by faith into the holy of holies, and see the work of Christ in the heavenly sanctuary, they perceive that they are a people of unclean lips,–a people whose lips have often spoken vanity, and whose talents have not been sanctified and employed to the glory of God.
Well may they despair as they contrast their own weakness and unworthiness with the purity and loveliness of the glorious character of Christ. But if they, like Isaiah, will receive the impression the Lord designs shall be made upon the heart, if they will humble their souls before God, there is hope for them. The bow of promise is above the throne, and the work done for Isaiah will be performed in them. God will respond to the petitions coming from the contrite heart. {4BC 1139.3}
For God sent not his Son into the world to condemn the world; but that the world through him might be saved. Anyone that believes on him is not condemned: but they that believe not are condemned already, because they have not believed in the name of the only begotten Son of God. And this is the condemnation, that light is come into the world, and people loved darkness rather than light, because their deeds were evil. For every one that does evil hates the light, neither comes to the light, lest their deeds should be reproved. But those who do the truth come to the light, so that their deeds may be made manifest, that they are wrought in God. (John 3:17-21)