In John 7:14-15, we are told that "about the midst of the feast [of Tabernacles] Jesus went up into the temple, and taught. And the Jews marvelled, saying, 'How knoweth this man letters, having never learned?'" From the reaction, it is clear that Jesus' teaching involved reading from the scriptures, and I have argued that the passage he read was likely Malachi 2:1-3:1.
Today I became aware of another possibility: Every seven years, during the Feast of Tabernacles (Sukkot), the king -- when there was a king -- was supposed to stand up in the temple and read from Deuteronomy. We are told in Mishnah Sotah 7:8 that Herod Agrippa (who reigned AD 41-44, just after the time of Christ) did this.
How is the portion of the Torah that is read by the king recited at the assembly, when all the Jewish people would assemble? At the conclusion of the first day of the festival of Sukkot, on the eighth, after the conclusion of the Sabbatical Year, they make a wooden platform for the king in the Temple courtyard, and he sits on it, as it is stated: “At the end of every seven years, in the Festival of the Sabbatical Year” (Deuteronomy 31:10).
The synagogue attendant takes a Torah scroll and gives it to the head of the synagogue that stands on the Temple Mount. And the head of the synagogue gives it to the deputy High Priest, and the deputy High Priest gives it to the High Priest, and the High priest gives it to the king. And the king stands, and receives the Torah scroll, and reads from it while sitting.
King Agrippa arose, and received the Torah scroll, and read from it while standing, and the Sages praised him for this. And when Agrippa arrived at the verse in the portion read by the king that states: “You may not appoint a foreigner over you” (Deuteronomy 17:15), tears flowed from his eyes, because he was a descendant of the house of Herod and was not of Jewish origin. The entire nation said to him: Fear not, Agrippa. You are our brother, you are our brother.
And the king reads from the beginning of Deuteronomy, from the verse that states: “And these are the words” (Deuteronomy 1:1), until the words: “Hear, O Israel” (Deuteronomy 6:4). And he then reads the sections beginning with: “Hear, O Israel” (Deuteronomy 6:4–9), “And it shall come to pass, if you shall hearken” (Deuteronomy 11:13–21), “You shall tithe” (Deuteronomy 14:22–29), “When you have made an end of the tithing” (Deuteronomy 26:12–15), and the passage concerning the appointment of a king (Deuteronomy 17:14–20), and the blessings and curses (Deuteronomy 28), until he finishes the entire portion.
The same blessings that the High Priest recites on Yom Kippur, the king recites at this ceremony, but he delivers a blessing concerning the Festivals in place of the blessing concerning forgiveness for iniquity.
Is it possible that Jesus read from Deuteronomy in the Temple during the Feast of Tabernacles, thus implicitly taking on the role of King of the Jews?
The first thing is to consider is the date. Was it a Sabbatical Year when Jesus taught in the Temple? Well, John 2:20 tells us that the first Passover of Jesus ministry was the 46th year of the construction of the Temple of Herod, which historians estimate to be around AD 27-29. This was after Jesus was baptized by John, and Luke 3:1-2 tells us that John didn't begin baptizing until the 15th year of the reign of Tiberius, which year began in September of AD 28. Passover is in March or April, so the best estimate for the first Passover of Jesus' ministry would be AD 29. After that, one more Passover is mentioned (John 6:4) and then the Feast of Tabernacles we are presently considering. Assuming there were no other intervening Passovers left unmentioned by the author, we can estimate that Jesus preached in the Temple in the fall of AD 30.
The Sabbatical Year in Agrippa's reign ended in AD 42, so the previous two Sabbatical Years would have ended in AD 35 and AD 28. Thus, based on such (admittedly spotty) chronological information as we have, it was not a Sabbatical Year when Jesus preached in the Temple.
Turning to the details in the Mishnah, we are told, rather confusingly, that the Torah reading took place "at the conclusion of the first day of the festival of Sukkot, on the eighth." What does "on the eighth" mean here? Sukkot is a seven-day festival, running from 15 to 21 Tishrei, so there is no eighth day of Sukkot, and no day of Sukkot is on the eighth of the month. And in any case, how could the eighth come "at the conclusion of the first day"? Anyway, we are told that Jesus appeared in the Temple "about the midst of the feast" -- and whatever the Mishnah is trying to say, it pretty clearly isn't talking about the middle of the festival. So even if it had been the right year for the king to read from Deuteronomy, it wasn't the right day.
Finally, the Mishnah describes a rather elaborate ceremony: The attendant gives the Torah scroll to the deputy high priest, who gives it to the high priest, who gives it to the king. In the absence of a king, some other "leader of the Jews" (someone of Nicodemus's class) would do the honors. It seems highly unlikely that some random Galilean rabbi would have been able to waltz in, take the Torah scroll, and read -- at least not on this special day.
I'm not sure how access to the scrolls would have been managed on other days. The Jews' surprise at discovering that Jesus is literate makes sense only if he has just read from the scriptures. Quoting bits of scripture from memory -- well, any Jew could do that, even John the Baptist, who lived in the desert and ate bugs.
In Luke 4:16-21, Jesus stands up in a synagogue, and "there was delivered unto him the book of the prophet Esaias," from which he proceeds to read. This was a local synagogue in Nazareth, though, and even there someone had to "deliver" the scroll to him. Would it have been as easy as that in the Temple itself, during a major festival? I guess the answer to that must be yes, since Jesus did read from the scriptures in the Temple. Perhaps during the less important middle days of the feast, the scrolls were made available to any rabbi who wished to preach.
All in all, I think Jesus' reading from the scriptures in the Temple during Sukkot was supposed to hint at his identity as Messiah -- but only in a broad way. Since it was not the correct year, nor the correct day, I don't think there would be any need for him to read from the correct book, Deuteronomy. I therefore stand by my earlier proposal that the book he read from was Malachi.