Was there a Jewish community in Corinth when Paul came to preach?
Yes, a large Jewish community existed in Corinth when the apostle Paul arrived. The city was a bustling commercial double seaport steeped in idolatry and paganism, and Paul came without fanfare to preach the gospel, resulting in multitudes of pagans converted.
Les explains that Corinth was a bustling double seaport city with a seaport on the east and a seaport on the west, and it was a commercial city with a lot of commercial activity. He notes that there was a large community of Jews. Into this ungodly city, the apostle Paul came with no fanfare and no advance men, and he simply began preaching the gospel: that Christ died for our sins according to the Scriptures, was buried, and rose again according to the Scriptures. That was the only gospel Paul knew, and out of that preaching came multitudes of pagans, and as seen in Acts, he turned the Roman Empire upside down.