1 Kings 8:10-11

When the priests were come out of the holy place That is, the most holy, where they had set down the ark. The cloud The usual token of God's glorious presence, Exodus 16:10; Exodus 24:15; Numbers 9:15; filled the house of the Lord In testimony of his gracious acceptance of this work and their service; and to beget an awe and reverence in them and in all others when they approached to God. So that the priests could not stand to minister By this it appears that the cloud filled the whole house, as well as the most holy place: for it was at the altar of incense in the sanctuary that the priests ministered. And it was either so bright that it dazzled their eyes; or rather, as the next verse seems to imply, so dark that it struck them with horror and amazement. Probably it was first excessively dark, and afterward broke out in overpowering light and splendour.