John experienced joy at Jesus’ response. A response which seemed at first a little stilted, a little stiff, but the perfect response to the prophet in prison.
Go back and report to John what you hear and see: The blind receive sight, the lame walk, those who have leprosy are cleansed, the deaf hear, the dead are raised, and the good news is proclaimed to the poor. Blessed is anyone who does not stumble on account of me. - Matthew 11:4
Jesus’ words sound a lot like a prophet that both Jesus and John were familiar with.
Then the eyes of the blind shall be opened,
and the ears of the deaf unstopped;
6 then the lame shall leap like a deer,
and the tongue of the speechless sing for joy. - Isaiah 35:5-6
And what’s more, John probably heard this little line that Jesus himself didn’t repeat, but John’s familiarity with Isaiah would have brought to mind, one verse earlier.
Say to those who are of a fearful heart,
‘Be strong, do not fear!
Here is your God. - Isaiah 35:4
Perfect words for a prophet in prison, on the verge of being overcome by his own doubts and despair. Let us take the risk of hearing Jesus speak to us in ancient words, spoken to other people, yet, in Scripture, spoken for our sake.