Your language may have a particular way of introducing the intended audience. Alternate translation: "am writing this letter to you in Corinth who believe in God"
Here "sanctified" refers to people who have been set apart as God's people. This can be stated in active form. Alternate translation: "to those whom Christ Jesus has set apart for God" or "to those whom God has set apart for himself because they belong to Christ Jesus" (See: [[rc://en/ta/man/jit/figs-activepassive]])
The word "name" here is a metonym for person of Jesus Christ. Alternate translation: "who call on the Lord Jesus Christ" (See: [[rc://en/ta/man/jit/figs-metonymy]])
The word "ours" includes Paul's audience. Jesus is the Lord of Paul and the Corinthians and all the churches. (See: [[rc://en/ta/man/jit/figs-exclusive]])