19 Now when it was late that same day, the first of the week, and the doors were shut, where the disciples were gathered together, for fear of the Jews, Jesus came and stood in the midst, and said to them: Peace be to you. 20 And when he had said this, he shewed them his hands and his side. The disciples therefore were glad, when they saw the Lord.
Bede: Wherein is shewn the infirmity of the Apostles. They assembled with doors shut, through that same fear of the Jews, which had before scattered them. . . . He came in the evening, because they would be the most afraid at that time.
Augustine: The shut door did not hinder the body, wherein Divinity resided. He could enter without open doors, who was as born without a violation of His mother’s virginity.
Chrysostom: It is wonderful that they did not think him a phantom. But Mary had provided against this, by the faith she had wrought in them. And He Himself too showed Himself so openly, and strengthened their wavering minds by His voice: And saith unto them, Peace be unto you, i.e. Be not disturbed. Wherein too He reminds them; of what He had said before His crucifixion; My peace I give to you [John 14:27]; and again, In Me ye shall have peace [John 16:33].
Gregory: And because their faith wavered even with the material body before them, He showed them His hands and side.
Augustine: The nails had pierced His hands, the lance had pierced His side. For the healing of doubting hearts, the marks of the wounds were still preserved.
Chrysostom: What He had promised before the crucifixion, I shall see you again, and you, heart shall rejoice [John 16:22], is now fulfilled.
Scripture from the Douay-Rheims Bible. Commentary from St. Thomas Aquinas, Catena Aurea, Vol. IV (London: Rivington, 1845).