In this quote from "d-day prayer," to what does the embolden pronoun refer?

almighty god: our sons, pride of our nation, this day have set upon a mighty endeavor, a struggle to preserve our republic, our religion, and our civilization, and to set free a suffering humanity.

Explanation:

You should note which pronoun you want to know about. Fortunately, there are only two "this" and "our."

Our refers to the entire nation and those living and praying in it. They all possess the young men (sons) whom the speaker is praying for.

this is a possessive pronoun. It means today. We may not be able to make the  same prayer tomorrow.

there is a sequence and logical steps to give an answer of a trouble.

1) strategy is necessary to develop an project idea.

2) to study and know the environment where you are going to work ( ecosystem).

3)   the materials resources to built the ideas.

4) to give a priority order in the context that you study. in this case human needs.