Cyril of Alexandria

He said not positively to them I am he, but rather leads them to the certainty of the fact, in order that receiving their faith in Him, with their reason agreeing thereto, they might return to him who sent them. Hence He made not answer to the words, but to the intention of him who sent them; as it follows, And Jesus answering said unto them, Go your way, and tell John what things you have seen and heard: as if He said, Go and tell John the things which ye have heard indeed through the Prophets, but have seen accomplished by Me. …

Catena Aurea by Aquinas ↗

Theophylact of Ohrid

These are also the words of Elias, saying, The Lord himself shall come and save us. Then the eyes of the blind shall be opened, and the ears of the deaf shall be unstopped. Then shall the lame man leap as an hart. (Isa. 35:4-6.)

Catena Aurea by Aquinas ↗

Bede

"Go," He said, "and tell John what you have seen and heard: the blind see, the lame walk, the lepers are cleansed, the deaf hear, the dead are raised, and, which is no less important, the poor have the Gospel preached to them." Either the poor in spirit, or certainly the poor in wealth, so that there is no distinction in preaching between the noble and the common, the rich and the needy. These things display the rigor of the Master and attest to the truth of the Teacher, as all are equal in His sight who can be saved. As He said:

On the Gospel of Luke ↗

Bonaventure

Second, he responds to the questioner by declaring the wonders seen and heard by the disciples; on account of which he says: And answering he said to them: Go and report to John what you have heard and seen, because, as is said in Tobit twelve, "it is honorable to reveal and confess the works of God." He commands them to declare what they have seen and heard, because these two senses show us very many distinctions, so that in this the more perfect faith of John is shown, who believed by hearing alone, than that of those who saw and …

Commentary on Luke, Chapter 7 ↗