Some have suggested the school of Tyrannus was a private synagogue, but this seems unlikely in that the text seems to imply Paul reasoned in the only synagogue in Ephesus. Rather, it was probably a private school run by someone named Tyrannus, and Paul was granted or perhaps rented the use of it for the afternoon hours of each day. We have an ancient text that adds information to the end of Acts 19:9, saying that Paul taught there “from the fifth hour to the tenth” [manuscript D Syriac (Western text)]. This was probably something that was written in the margin of a manuscript and ended up in the text itself through a copy error. The point is, the information probably represents either an authentic tradition that those were the hours Paul used to teach there, or those were the hours schools of this kind were normally unused by the owner and could be rented out for other public purposes.
This seems to have been Paul’s normal procedure upon leaving or being expelled from the synagogue of any city. He normally used a large residence offered by one of his more prominent and wealthy disciples or rented an establishment whereby he could reason and persuade people, whether Jew or gentile, that Jesus is the Christ, the Savior of the world. In Philippi, Paul worked from Lydia’s home (Acts 16:14-15), and in Thessalonica it seems he operated from Jason’s home (Acts 17:5-9). In Athens he used the marketplace and the Areopagus, probably because the few believers there may not have owned a suitable place for public discussion, or if they did, didn’t offer it to Paul for the sake of the Gospel. However, when he arrived at Corinth, he used the residence of Justus (Acts 18:4-7), which seems to have had a common wall with the local synagogue there.
These places were used by Paul to discuss freely anything and everything which pertained to the Scriptures. In the synagogue one could do this to a point. Once it was considered offensive, the Gospel could not be preached there. For example, it seems that Jesus could be preached as long as the gentiles were not equally accepted alongside the Jews. Once the Jews understood they had to give up their favored status with God, that is, that men were justified by faith rather than works (their traditions), the Gospel of Christ was no longer welcome. The synagogues in Palestine did not hinder the Gospel, as long as their traditions were not brought into question. In other words, saying one was justified by faith in Jesus, but still practicing the traditions of the elders (Jewish tradition), never really brought those traditions into question, because it was the Jewish culture. It was simply the way all religious Jews lived. This is what is meant when the Scripture says Paul was the apostle to the gentiles but Peter to the Jews. Paul preached gentiles didn’t have to become Jews to be saved. This was not a problem in Judea and Galilee. Most, if not all, believers were Jews, and believers simply practiced the traditions of the elders. It was the Jewish custom or culture. Jesus was not against the practice, unless those traditions of men interfered with the truth or the commands of God. He practiced those very customs, until the Pharisees began blaming some of Jesus’ less kosher disciples for wrongdoing (Mark 7:1-9).
We often criticize the Jewish synagogues unjustly, saying they were against Christ. Actually, this is not true. The Jews most certainly rejected Jesus as their Messiah eventually, but it was not necessarily so from the beginning. The fact is, one could hardly preach or teach in any of our own Christian denominations as freely as Paul preached in the Jewish synagogues of the first century. The Jews put up with Paul’s “freedom in Christ” for two weeks at Antioch of Pisidia, three weeks at Thessalonica, for an unknown number of weeks at Corinth and three months at Ephesus. I hardly think anyone who took issue with any of the traditions peculiar to any one of our Christian denominations would be allowed to preach or teach for a moment longer than the teaching was found out.
We need to understand that Paul was not preaching anything major being wrong per se with Judaism. He believed in the same God that was worshiped throughout Palestine and the Diaspora. He used the very same Scriptures they used and taught the very same things out of the Law and the Prophets. When he was among Jews, he lived as a Jew (1Corinthians 9:20). Jesus was not the problem from the beginning. It was always the traditions of men—the traditions of the elders that turned the Jews against the Gospel of Christ. The same is true today in our own denominations. Many (not all) of our brethren in one denomination are taught and believe that other Christians who don’t worship God in their specific denomination (i.e. those who don’t hold to their specific human doctrines) are not really believers at all. This is wrong. This type of “tradition” is what got Paul expelled from the synagogues, and this human tradition was never taught by him in the “schools” such as the one of Tyrannus in Ephesus.