How do we know that union with Christ is true?

Our confidence in the truth of union with Christ comes from the authoritative witness of Scripture and the historical and personal evidence of God's transformative work in individual lives. Jesus, in His prayer for unity in John 17, assures us of the exclusive nature of this union for those whom the Father has given Him. Believers experience this union as they receive faith—an act of God's grace—which is not of their own doing, but the evidence of life in Christ. The fulfillment of His promises and the continual work of the Holy Spirit in the lives of believers provides assurance of the reality and significance of this union, marking them as His own.