This question seems to be incomplete. However, there is enough information to find the right answer.
Answer:
The "present" is the news of people being selected to be killed in the concentration camp.
Step-by-step explanation:
In Night (1960), by Elie Wiesel, when he describes the SS offering them "a beautiful present for the new year," he´s using Verbal or Situational Irony. They were not given a present, but horrible news: selection was coming, meaning that some of them, whose who were too frail to work, would be killed. The narrator will find out that his father had been chosen to be sent to the crematorium.