What does the poet ask us to remember in the first stanza of the poem "No Men Are Foreign"?

The poem actually consists of just one stanza, comprising twenty lines. The first line of the poem—"Remember, no men are strange, no countries foreign"—conveys its disarmingly simple message: beneath the surface, we're all the same. The human race may be divided up into different genders, religions, nationalities, and so on, but it's still just one race all the same, which is something we all too often overlook. If we look at other people simply as human beings instead of as Americans, Mexicans, or Canadians, for example, then we'll realize that the concept of a foreigner is ultimately of no importance.
Not only do we all share a common humanity, we also share the same earth:

the land our brothers walk uponIs earth like this, in which we all shall lie.

And on this land, wherever and whoever we are, we all enjoy the blessings of a bountiful harvest and suffer the ravages of war. And the main reason behind war is that we fail to see the common humanity beneath the uniform. All too often, we're told to hate other people, simply because of their different race, religion, or nationality. But the speaker wants us to realize that, because we're all ultimately the same, when we hate other people, we're actually hating ourselves:

Let us remember, whenever we are toldTo hate our brothers, it is ourselvesThat we shall dispossess, betray, condemn.
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