Jesus stood in the midst of them - This was when the apostles were assembled, and when they had closed the doors for fear of the Jews, John 20:19. It was this fact, as well as his sudden and unexpected appearance, that alarmed them. The doors were shut, and the suddenness of his appearance led them to suppose they had seen a spirit.
Peace be unto you - This was a form of salutation among the Hebrews denoting a wish of peace and prosperity. See Genesis 43:23. It was especially appropriate for Jesus, as he had said before his death that he left “his peace” with them as their inheritance John 14:27, and as they were now alarmed and fearful at their state, and trembling for fear of the Jews, John 20:19.