Isaiah 6:2. “Above it stood the seraphims; each one had six wings; with twain he covered his face, and with twain he covered his feet, and with twain he did fly.”
The seraphim who were above the throne were there in attendance, not superiority. They are different from the cherubim; they are the fiery guardians of the holiness of the Lord. They have certain human features: Their faces were covered in awe. They didn’t dare to gaze at God’s glory. Their feet were also covered, in acknowledgment of the lowliness of their glorious service. The third set of wings kept them hovering over the throne. The verb tense that is used here indicates an continuous, ongoing service.
What a gift Isaiah was given, to actually get this little glimpse of heaven. How amazing it must be!