"Then one day they expelled all the foreign Jews of Sighet. and Moshe the beadle was a foreigner." Why does Wiesel say this so abruptly?Any help is...

Elie Wiesel is quite emphatic about the cruelty of the Nazis.  At the same time, he holds a great deal of anger towards Jewish individuals who failed to speak out and act in a manner that defied indifference.  Throughout Night, we see instances where the cruelty and dehumanization the Nazis showed towards Jewish individuals, similar treatment is shown with Jewish individuals towards one another.  It creates a vicious cycle of human cruelty as the habits of silence and denial are passed down from tormentor to tormented.

Wisel's abrupt and sudden statement of Moshe's departure reflects how the community react to Moshe and his narrative of what happens to those taken by the Nazis.  Rather than seeing him as a member of their own community, someone whose spiritual function and basic principles as a human being should be recognized by the community and protected by it, the dismissal of all "foreign born" Jewish people allowed the community of Sighet to treat Moshe as someone who is dispensable. Their dismissal of him is an attempt to save their own senses of self by sacrificing another.  This becomes not only a theme of the work, but one of Wiesel's hauntingly powerful statement about the true terror of the Holocaust.  A major atrocity was the severance of bonds between people.  The community dispelled bonds with Moshe out of expedience.  This same behavior will be displayed with Madame Schachter, and will continue when people fight with one another for a piece of bread, and fathers and sons can no longer show loyalty and attachment to one another as the need for survival overwhelms the basic sensibility of compassion for one another and connection to one another.  While Moshe is accepted in an overall manner, when he describes the horrors he witnessed, he is dismissed and his perceptions are discarded by the community. In the statement, Eliezer speaks of how the community ends up viewing Moshe, and how this abrupt spirit if disassociation and detachment become one of the most horrifying crimes of the Holocaust.  While we react with horror and shock of the rupturing of bonds and connections that are supposed to bind and connect one human being to another, such dismissal was sadly quite common in times of unimaginable horror.