Jamieson, Fausset and Brown on Ezekiel 9:3

3. glory of ... God--which had heretofore, as a bright cloud, rested on the mercy seat between the cherubim in the holy of holies (2Sa 6:2; Psa 80:1); its departure was the presage of the temple being given up to ruin; its going from the inner sanctuary to the threshold without, towards the officers standing at the altar outside, was in order to give them the commission of vengeance.