Meaning of "for indeed"?

This is, how I see it, a combination of words used outside any commonplace English use. For situations like these, I going back to the basics and look at a dictionary definition of all the words, and attempt to draw a meaning.

(I am using Merriam Webster.)

Here is "for" that could apply:

Used as a function word to indicate purpose.

Used as a function word to indicate an intended goal.

Used as a function word to indicate the object or recipient of a perception, desire, or activity. (It seems as if your quote is leaning toward this meaning.)

These meanings are connected with other expressions like "for certain," "for sure," "for [purpose]."

Here is "indeed" that could apply:

All things considered[;] as a matter of fact.

When we read Woodrow's lines, we see that he is attempting to draw attention to some conclusion when one thinks "about it", which is a similar premise to "consider[ing]," as in the definition.

For extra consideration, I looked up other uses of "for indeed"; I found this Bible quote (the first) of Luke 1:66, and I also found this quote (the second) from the Quran (94:5):

"For indeed, the hands of the lord was on him."

"For indeed, with hardship [will be] ease."

The use of "indeed" here seems to differ in an interpretive meaning from Woodrow's quote, but the basic idea we can get is this:

For: To identify the object/recipient of a view (here it is "indeed").

Indeed: As a matter of fact; everything considered.

This can define the construction "for indeed" possibly as "For a matter of fact," as "indeed" (used to show certainty) is connected to "for" (which identifies a purpose).

To connect this to your quote, Woodrow is saying that if one stops and thinks, they can realize some truth about the current situation; since "indeed" is commonly used to indicate some obvious truth, the addition of "for" adds a nuance of purpose/receiving action.

(I see I explained this in a very interpretive and convoluted way (I did not even consider the fact that "indeed" is an adverb), so by all means if someone is able to provide a more direct and concrete answer. I hope that this still can help you form some type of idea.)

EDIT: Jim's comment goes through a much more simpler reasoning: It is simply reinforcing the statement, like what "yea," "forsooth," or "indeed" alone would do.