C. F. Keil and Franz Delitzsch on Numbers 16:42

Num 16:42

When the congregation assembled together, Moses and Aaron turned to the tabernacle, and saw how the cloud covered it, and the glory of the Lord appeared. As the cloud rested continually above the tabernacle during the time of encampment (Num 9:18.; Exo 40:38), we must suppose that at this time the cloud covered it in a fuller and much more conspicuous sense, just as it had done when the tabernacle was first erected (Num 9:15; Exo 40:34), and that at the same time the glory of God burst forth from the dark cloud in a miraculous splendour.