The hearers were amazed. Jesus taught the Scriptures with depth, yet He had not trained under the recognized teachers. Barnes explains that "the Jewish letters or science consisted in the knowledge of their Scriptures and traditions," and that Jesus showed "such a profound acquaintance with the Old Testament as to excite their amazement and admiration." Since the law was taught "in celebrated schools" Jesus had not attended, they could not account for it. Gill says they marvelled "both at the matter, and manner of his doctrine." Their question presses for the source of His learning.

Jesus answers the question of source directly: "My doctrine is not mine, but his that sent me" (John 7:16). He then gives them a way to test it: "If any man will do his will, he shall know of the doctrine, whether it be of God, or whether I speak of myself" (John 7:17). He adds that one who seeks the glory of the one who sent him "is true, and no unrighteousness is in him" (John 7:18).

The word "letters" is grammata, writings or learning. Gill notes that some ancient versions render it "the Scriptures," and that the Scriptures are called "holy letters" in 2 Timothy 3:15, where the KJV reads "holy scriptures." "Having never learned" translates memathekos, a form of the verb for learning or studying, which the interlinear glosses "having studied."

Barnes notes that the Jews taught their law and traditions in schools, and that we do not know what early teaching Jesus had, except that "it was customary for the Jews to teach their children to read the Scriptures." Matthew Henry sums it up: Christ "was mighty in the scriptures, though he never had any doctor of the law for his tutor."

Jesus' answer turns the question from His schooling to His sender. His teaching did not come from a school; it came from the Father who sent Him (John 7:16). This is a claim about who He is, and it fits John's whole Gospel, where Jesus again and again speaks as the One sent by the Father (John 7:28-29).

Jesus also shows how a person comes to know the truth of His words: not by credentials, but by willingness to do God's will (John 7:17). The wonder of the crowd was a good start, but wonder alone did not settle the question. Others had the same reaction in His own country: "Whence hath this man this wisdom?" (Matthew 13:54). Later, the rulers marvelled the same way at Peter and John, "unlearned and ignorant men," and "took knowledge of them, that they had been with Jesus" (Acts 4:13).