Your language may have a particular way of introducing the author of a letter and the intended audience. Alternate translation: "I, Paul, wrote this letter to you in Corinth who believe in God"
This indicates that both Paul and the Corinthians knew Sosthenes. Alternate translation: "Sosthenes the brother you and I know" (See: [[rc://en/ta/man/translate/translate-names]] and [[rc://en/ta/man/translate/figs-explicit]])