From The Gospel of John, by Francis Martin and William Wright, commenting on John 20:20:
During the Farewell Discourse, Jesus told his disciples that they would “weep and mourn” (16:20) and be “in anguish” (16:22) when he left them. He also reassured them, “I will come back to you” (14:28) and “you will see me” (16:16).
Now Jesus fulfills this promise: he came and stood in their midst. And he speaks the words of shalom, the †eschatological reconciliation between God and his people: Peace be with you (see Isa 52:7; 57:19). Before he departed, Jesus told his disciples, “Peace I leave with you; my peace I give to you. . . . Do not let your hearts be troubled or afraid” (14:27). The risen Jesus now gives the disciples the gift of his peace, which drives away their fear, for he incorporates them into communion with the Father. !rough his cross and resurrection, Christ has “conquered the world” (16:33) and its ruler (12:31), and he has made his disciples “children of God” (1:12). There is, then, no reason for his disciples to fear. The presence of the wounds of crucifixion on the risen Jesus’ body is significant. They indicate that the body resurrected to glory is the same one that died on the cross (see Luke 24:39).14 Resurrection is not the return of a human being to ordinary mortal life but total transformation into a glorified mode of existence. As St. Paul wrote, the natural body is transfigured by the Holy Spirit into a glorified, “spiritual body” (1 Cor 15:44). The wounds on Jesus’ resurrected body reveal that he is forever fixed in the act of love in which he died. The love and sacrifice that he offered on the cross are forever present before the Father as “expiation for our sins, and . . . for those of the whole world” (1 John 2:2).
Jesus’ wounds also signify that the victory of the resurrection comes only through the cross. Similarly, the Lamb in the book of Revelation bears the wound of his slaughter by which he accomplished the work of redemption (Rev 5:6, 9). In this way, St. Thomas Aquinas, drawing on the Venerable Bede, can speak of the wounds on Jesus’ resurrected body as “trophies” of his victory.
Donatien Mollat found significance in John’s use of the verb “showed.” After the temple incident (2:14–17), the †Jews asked Jesus to “show” them a sign to legitimate his words and deeds (2:18). Jesus responded with a statement about raising up the temple of his body (2:19). Now, when Jesus shows the disciples his risen body with its wounds, he provides the †sign that legitimates his words and deeds: his resurrection.