Jesus saw their fear and named it. They "were terrified and affrighted, and supposed that they had seen a spirit" (Luke 24:37). Gill explains that they could not tell "whether what they saw was Jesus, or an apparition, which gave them a great deal of trouble and uneasiness, and filled them with fright and terror." The first question speaks to their alarm. The second goes deeper, to the doubts rising inside them. Barnes reads it as a reproof for doubting whether He was truly the Messiah: they had the words of the prophets, Jesus' own earlier predictions, and the report that He had risen, and still they doubted.

Jesus did not wait for an answer. He gave them evidence: "Behold my hands and my feet, that it is I myself: handle me, and see; for a spirit hath not flesh and bones, as ye see me have" (Luke 24:39). Then "he shewed them his hands and his feet" (Luke 24:40). When they still "believed not for joy, and wondered," He asked for food and ate it before them (Luke 24:41-43). Finally He reminded them of His words and "opened he their understanding, that they might understand the scriptures" (Luke 24:44-45).

The KJV word "troubled" translates tetaragmenoi, from a verb meaning to stir up or agitate. "Thoughts" is dialogismoi, inward reasonings; the ESV renders it "doubts." Barnes says the word here means "doubts" or suspicions, and points to 1 Timothy 2:8, where the same idea appears in "without wrath and doubting." The verb "arise" literally means to come up, as if the doubts were rising up in their hearts.

The timing matters. Just before this, the group had been saying, "The Lord is risen indeed, and hath appeared to Simon" (Luke 24:34). John's account of the same evening says the doors were shut "for fear of the Jews" (John 20:19), and Gill notes that Jesus appeared among them without being heard or seen coming in.

Jesus meets fear with questions and then with Himself. He does not leave them in their fear. He invites them to look and to touch. Gill points to the night on the sea when the disciples "were troubled, saying, It is a spirit" (Matthew 14:26), as an example of the fright people feel when they think they see an apparition. That night Jesus answered, "Be of good cheer; it is I; be not afraid" (Matthew 14:27). Both times He names their fear and shows them who He is.

The risen Jesus is not a ghost or an idea but the same Lord with a real body. Barnes says, "He appealed to their senses, and performed acts which a disembodied spirit could not do." Luke shows the risen Lord seen, offering Himself to be handled, and eating before people who did not expect it (Luke 24:39-43).