John Calvin on John 20:20

20. He showed them his hands and his side. It was necessary to add this confirmation, that by all these methods they might be fully assured that Christ was risen. If any person think it strange and inconsistent with the glory of Christ, that he should bear the marks of his wounds even after his resurrection, let him consider, first, that Christ rose not so much for himself as for us; and, secondly, that whatever contributes to our salvation is glorious to Christ; for, when he humbled himself for a time, this took nothing away from his majesty, and now, since those wounds, of which we are speaking, serve to confirm the belief of his resurrection, they do not diminish his glory. But if any person should infer from this, that Christ has still the wounded side and the pierced hands, that would be absurd; for it is certain that the use of the wounds was temporary, until the Apostles were fully convinced that he was risen from the dead.

Then were the disciples glad when they saw the Lord. This means, that all the grief which had been occasional to them by the death of Christ was dispelled by his new life.