In the first sample for Isaiah chapter 4, the Lord makes a connection to the 4th book of the Bible with the cloud by day and the pillar of fire by night.
And the LORD will create upon every dwelling place of mount Zion, and upon her assemblies, a cloud and smoke by day, and the shinning of a flaming fire by night…
So it was always: the cloud covered it by day, and the appearance of fire by night.
In the second sample for Isaiah chapter 4, the Lord makes a connection with God burning away the undesirable.
When the Lord shall have washed away the filth of the daughters of Zion, and shall have purged the blood of Jerusalem from the midst thereof by the spirit of judgment, and by the spirit of burning.
And when the people complained, it displeased the LORD: and the LORD heard it; and his anger was kindled; and the fire of the LORD burnt among them, and consumed them that were in the uttermost parts of the camp.