How do we know that believers are one in Christ?

The oneness of believers is established through the shared faith in Jesus Christ as Lord and Savior. According to Ephesians 4:5, there is one Lord, one faith, and one baptism, which serves as a public declaration of this unity. Every believer has the Holy Spirit and a common hope that binds them together. This spiritual unity is not based on external differences but on the essential truth that all members of the church are united in Christ, cleansed by His blood and identified by His righteousness.