This account in the Literary Encyclopedia helps me in my attempts to try and to make sense of what Levinas understands ethics to be in the concrete conditions of everyday life. It says:

'The word [ethics] does not mean what we ordinarily expect. It is defined very early in Totality and Infinity: "We name this calling into question of my spontaneity by the presence of the Other, ethics." (p.43) Ethics is a way of talking about the encounter between the self and the other. But what could it mean to start with a movement whereby the self is called into question?'

"The encounter of the self with the Other, and specifically with the face of the Other. Face, like ethics, is for Levinas a technical term. It is "[t]he way in which the other presents himself, exceeding the idea of the other in me." (1967, 50) In the concrete conditions of everyday life, the encounter with the face of the other is the encounter with infinity because of the way in which the face always transcends what I has expected."

But why is this encounter ethical? We could continue to refuse hospitality. We could demand that they continued to be locked up or sent back to wher they came from.