Luke 24:37

“But they were terrified and affrighted, etc.] At the sight of him, and at his sudden appearance among them, without being heard, or seen before, and the doors shut and bolted; they could not tell how to account for it, that it should be Jesus himself risen from the dead in his own body, though they had been just speaking of his resurrection, and had had a confirmation of it from the disciples that went to Emmaus: and supposed that they had seen a spirit; that what they saw was a phantom, or apparition, or a spirit, that had assumed, and appeared in, the shape of Jesus, and was not he himself.”

“a spirit--the ghost of their dead Lord, but not Himself in the body (Act 12:15; Mat 14:26). thoughts--rather, "reasonings"; that is, whether He were risen or no, and whether this was His very self.”

“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,…”

“Luk 16:30; Sa1 28:13; Job 4:14-16; Mat 14:26, Mat 14:27; Mar 6:49, Mar 6:50; Act 12:15 Luke 24:38”