John 20:20

And when he had said this, he showed unto them his hands and his side. The disciples therefore were glad when they saw the Lord.

Christ showed them also the wounds in his feet and ate a piece of broiled fish in their presence (Luke 24:36-43). He asked them to handle his body and to be fully convinced of his reality, thus fortifying them forever against any thought that they had merely seen a vision of him, or that his presence was just a spiritual manifestation.

Glad when they saw the Lord ... This appearance before twelve men (including the two from Emmaus) was authentic and convincing; and they who saw it never wavered or doubted afterward. It was even repeated a week later when Thomas had rejoined them; and this double epiphany to the Twelve constituted the very foundation of Christian evidence. This was the sacred fountain that supplied the evangelistic zeal of the apostles. The certainties established in these scenes enabled them to stand before the whole world shouting the message of redemption in Christ. The conviction made final and permanent by these events sustained them in the fires of persecution and death. The Galilean had triumphed! If the facts here related did not occur, then what did happen? Skepticism has no answer. For nearly two millenia the wisest and best have received this narrative as sacred Gospel. The record here is the truth, and it shall stand forever.