Isaiah 6: 4. “And the posts of the door moved at the voice of him that cried, and the house was filled with smoke.”
The voices of the seraphim calling to each other were so powerful that the very foundations of the doorposts were moved, as in an earthquake. The smoke that filled the temple was the outcome of the worship of the seraphim; it arose from the altar of incense. That Isaiah was privileged to see this incredible heavenly activity was an indication of his own acceptance by God, the the preparation for his testimony.
This vision of the Lord is in stark contrast to the dishonor done Him by His people. It tells us that the day is coming when His holiness and glory will be visible to all people in all the corners of the earth.
What comes next is Isaiah’s response to this vision, and his commission to preach to the people.