How are we to know when God arrives if, in our doubt, our capacity for seeing God is sure to fail? John gives an answer to this question that brings us to the heart of faith’s peculiar form of knowing
linking the resurrection of Jesus to the act of commissioning disciples for their own task.
That their joy is not an end in itself becomes immediately clear with Jesus’ repeated words of peace and his commission, “As the Father has sent me, so I send you.” The Gospel has already established that God sends Jesus and Jesus in turn sends the disciples (3:17; 13:20; 17:18), but here the commission is marked by the gift of the Holy Spirit
His final words to Thomas, rendered by the NRSV as “Do not doubt but believe,” would be better translated as “Do not be unbelieving but believing.” The emphasis is on Jesus’ invitation to see and believe, not on castigating Thomas.