What does "a cloud of smoke by day and the shining of a flaming fire by night" mean? 2 Nephi 14:5

What does "a cloud of smoke by day and the shining of a flaming fire by night" mean? 2 Nephi 14:5

This by far was my favorite question to answer this week. I thought of the answer as I was sitting in church behind the organ, taking the sacrament. It was a really good feeling.

Nephi is quoting his younger brother Jacob who is quoting Isaiah 4. They are discussing the millennial day - when Jesus Christ will return to earth again.

The promise is that the Lord will create a cloud and smoke in the daytime and a shining flame of fire in the night to belong on every home in mount Zion, and that this will be a defense.

I was confused about the smoke and the flame metaphor, but I thought about it a little bit. This answer comes from my thoughts, not from searching other scriptures and concordances. It would be interesting to study this that way eventually.

Smoke and flames have a physical presence. At night, a fire illuminates darkness and is visible from very far away. Meanwhile, smoke during the day is also visible from a great distance.

What would being visible from a great distance have to do with defending the homes of those who have made covenants with God - with the saints of Zion?

I wonder if this could be a metaphor for communication across impossibly great distances. This world of instant communication in which we live definitely has some specific digital tools that are highly strengthening to the spirituality of saints - and all people in general.

Whatever the metaphor symbolizes specifically, it is clearly about constant visibility, a constant, steady presence - something that is tangible, powerful, and clear. You can't miss a flaming fire when you walk by it. You can't miss a giant cloud of smoke, either. Ever see a forest fire? I have. You can't avoid the smoke.

Something about the people who live on mount Zion will be visible, powerful, clear, and undeniable. I guess the next question is who lives on mount Zion, where is it, and how can I get there?

The answer to what Zion is and who lives there is in Latter-day scripture:
Doctrine and Covenants 97:21 clearly says that Zion is the pure in heart.

I am not sure I know exactly what that means yet, but I will try to find out.

Addendum: this is also a reference to the Lord leading the Israelites out of Egypt.