This verse from the Letter of Jeremiah 6:61 (or Baruch 6:61, depending on the Bible translation) speaks to the universality and naturalness of certain phenomena, and contrasts them with the perceived uselessness and lifelessness of idols. Let's break it down:

"Likewise also the lightning when it glittereth is fair to see..." This refers to the visual beauty and power of lightning. It's a natural phenomenon that's awe-inspiring and noticeable.

"...and after the same manner the wind also blows in every country." This points to the widespread and common nature of the wind. It affects all places, regardless of where people are.

Meaning in Context:

The Letter of Jeremiah is a polemic against idolatry. It argues that idols are powerless, senseless, and unable to do anything for their worshippers.

In this verse, the author is using lightning and wind as examples of natural phenomena that are demonstrably real and effective. They are comparing these natural forces to idols that do nothing and go nowhere.

The contrast being drawn is:

Lightning and Wind: These are natural, powerful, and universal forces. They exist independently and affect the world.
Idols: These are man-made, powerless objects that are confined to a specific location and have no real influence.

Therefore, the verse is intended to highlight the absurdity of worshipping idols when there are so many other real and powerful forces in the world. The author is suggesting that if you're going to worship something, it should be something that demonstrably exists and has an impact, like lightning or wind, rather than a lifeless idol.

Essentially, the verse is part of a broader argument to ridicule idolatry and encourage people to abandon the worship of inanimate objects.