Isaiah 53 the missing haftorah?
Is Isaiah 53 the forgotten Haftorah or the forbidden chapter as asserted by Christian missionaries? The missionary claim is that this chapter has been left out of the Haftorah cycle because the “rabbis” knew that if we read this chapter, we would know that Jesus is the Jewish messiah, and they certainly couldn't have that! In order for this claim to be true, the custom of reading the Haftorah or prophets in the Synagogue on Shabbat would have to have been established after Jesus’ death, to intentionally counteract the Christian claims. However, we know that the custom of reading the Haftorah began many years before Jesus.
Although there are some commentators who date the institution of reading the Haftorah to Ezra the scribe, who lived during the time between the First and Second Temples, most authorities explain that the custom of reading the Haftorah began during the time that the Greeks ruled over the land of Israel.
The Hellenist government forbade the reading of the Torah, but not the Prophets. So instead of reading the Torah portion each week, the Jews started reading a portion of the Prophets which contained ideas that were similar to the Torah reading of that week (Abudraham, Levush). When the Jews won their freedom, the custom of reading the Prophets continued, being added to the Torah service, and was officially instituted as part of the formal prayer service. This took place during the early part of the Second Temple period.
The vast majority of the Haftorahs were chosen because they share a common them with the Torah portion. Not every part of the Prophets is read as a part of the yearly cycle, only those whose theme matches a Torah portion. Now, there are some exceptions - when the haftorah is chosen because it reflects the time of the year. For example, during the Three Weeks of mourning for the Holy Temples we read prophecies which warn of the impending destruction which will occur if the Jews don't repent. On the Shabbat before Yom Kippur we read about repentance, etc.
With this understanding of why the sections of the Prophets were chosen, it is easy to see why Isaiah 53 was left out of the reading cycle. Its not some great rabbinic conspiracy, it didn't match any of the Torah portions as well as some other sections of Isaiah do. That's all there is to it.
Although not necessary, it may be interesting to note that in the New Testament book of Acts, chapter 13, we read of an occasion where Paul is in the Synagogue on Shabbat. The book of Acts is said to have taken place immediately after the death of Jesus. That being the case, there would not have been enough time between the birth of Christianity and the events in the book for the Rabbis to have instituted a new custom in order to counter the new religion.
After the reading of the Law and the Prophets the synagogue officials sent to them, saying, "Brethren, if you have any word of exhortation for the people, say it."
This tells us that both the Torah and the Haftorah were being read in the synagogue during the time of Paul, which was very shortly after the death of Jesus and clarifies for us that this custom was established before the birth of early Christianity, and not in response to it.