Acts 18:4 And he reasoned in the synagogue every Sabbath, and persuaded both Jews and Greeks.
There was a temple in Corinth where the Jews would meet every week on their Sabbath day as was their custom.
Paul took this opportunity to go to the temple every week and speak to them showing them how Jesus fulfilled the scriptures in every way.
He continued to work during the week but made sure he took time out every week from work to be with other people to share the Gospel.
Paul tried to get all people to accept the Gospel whether they were Jews or Gentiles; he wanted them all to embrace God’s Word.