Different peoples and the Gospel

Today, especially in the presidential campaign, immigration and racism are becoming huge issues. Donald Trump gets cheered by many for wanting to build a wall between the United States and Mexico, and for banning Muslims, or at least using "extreme vetting." His description of the lives of black Americans (having lousy salaries, housing, schools, etc.) suggests that he knows little about middle class African-American lifestyles.

All this raises the question: How do we treat people who are different from ourselves? Do we fear them, use derogatory language to describe them, keep ourselves separate from them? Or do we welcome them, learn from them, and make them neighbors?

In the Gospels, of course, Jesus often offered positive views of Samaritans, who were not Jews and were often regarded by Jews as "outsiders" who could be shunned. Recently, the readings from Scripture on Sundays have struck me as having a message about that. In the first reading from Isaiah on a recent Sunday, Yahweh says:

I come to gather nations of every language;
they shall come and see my glory.
I will set a sign among them;
from them I will send fugitives to the nations:
to Tarshish, Put and Lud, Mosoch, Tubal and Javan,
to the distant coastlands
that have never heard of my fame, or seen my glory;
and they shall proclaim my glory among the nations.

The takeaway? God seems to love and accept all peoples of the earth, and in readings like this, God implicitly encourages others to do the same. God seems to be an immigrant lover -- one who says "y'all come!"

Why do I get the feeling that this is not interpreted or preached that way very often?