The Christians in Jerusalem were hesitant to accept Paul (formerly Saul) for a few key reasons, rooted in his past and their understanding of the Christian faith at the time:
* Paul's Violent Persecution of the Church: Before his conversion, Paul was a zealous Pharisee known for his fierce persecution of Christians. He actively sought them out, imprisoned them, and even participated in their stoning (e.g., Stephen). This reputation preceded him, and the Jerusalem Christians naturally feared and distrusted him. They couldn't easily believe that such a fervent persecutor had truly become a follower of Jesus.
* Concerns about his Theological Views: As Paul began preaching to Gentiles and advocating for their inclusion in the Christian community without strict adherence to Jewish law (circumcision, dietary laws, etc.), his views were seen as controversial and potentially heretical by some Jewish Christians in Jerusalem. They worried that he was undermining the importance of Jewish tradition and the Law for believers in Jesus. Some may have suspected that he was compromising the core tenets of their faith to appeal to Gentiles.
* Skepticism about his Conversion: The radical nature of Paul's conversion experience (the encounter with the risen Christ on the road to Damascus) raised doubts among some in Jerusalem. They might have questioned the validity of his conversion or his motives, suspecting that it could be a trick to infiltrate and undermine the church from within.
* The Need for a Mediator/Introducer: The account in Acts 9 describes how Barnabas, a respected member of the Jerusalem church, took Paul under his wing and vouched for him to the apostles. This highlights the fact that Paul needed someone to vouch for his sincerity and help bridge the gap of mistrust. The apostles likely held some reservations until Barnabas explained Paul's conversion experience and affirmed his commitment to the Gospel.
In summary, the initial hesitation towards Paul in Jerusalem stemmed from his history of persecution, concerns about his theological views, skepticism about his conversion, and the need for a trusted figure to vouch for him. Over time, as Paul's ministry and teachings became more widely known and accepted, and as he demonstrated his commitment to the gospel, these concerns gradually diminished.