In the poem "No Men Are Foreign," written by James Kirkup, who are being referred to as brothers, and what two things are common to all?

In James
Kirkup's poem "No Men Are Foreign" he writes that "attacking other humans is
attacking our brothers." So, while he does not specifically refer to anyone directly, his
statement implies that all humans are our brothers.  The two things that he notes as being
common to all are " eyes, like ours, that wake or sleep" and " strength that can
be won by love."