The angels tongues are pure praise. Fire is also praise, the flickering flames are praise. Voice is praise, hearing is praise. All these images of praise are images of movement: fire moves, wind moves, tongues move, breath moves, hearing moves. In this praise there is a reverse movement toward God, perhaps mirroring. Energy moves out from God through the angels, and this movement back toward God in the form of praise is vibratory, dynamic, and meaningful.
All the angels are amazed at humans, who through their holy works appear clothed with an incredibly beautiful garment. For the angel without the work of the flesh is simply praise; but the humans with their corporeal works are a glorification! Therefore the angels praise humans' work.