Not like the brazen giant of Greek fame,
With conquering limbs astride from land to land;
Here at our sea-washed, sunset gates shall stand
A mighty woman with a torch, whose flame
Is the imprisoned lightning, and her name
Mother of Exiles. From her beacon-hand
Glows world-wide welcome; her mild eyes command
The air-bridged harbor that twin cities frame.
"Keep, ancient lands, your storied pomp!" cries she
With silent lips. "Give me your tired, your poor,
Your huddled masses yearning to breathe free,
The wretched refuse of your teeming shore.
Send these, the homeless, tempest-tost to me,
I lift my lamp beside the golden door!
This continues a tradition as old, or older than the  New Testament,  comparing physical uncleanliness with moral unworthiness. In this case Emma is asking for the most wretched refuse. This is a very Christian urge, and also a nod to the fact that many early colonists were forced from their homeland due to religious persecution. 

The New Colossus