Why is it important for Christians to understand their union with Christ?

The believer's union with Christ is a foundational aspect of Christian faith. This union means we are 'bone of His bone and flesh of His flesh' (Ephesians 5:29), signifying an intimate relationship where His life and righteousness are imputed to us. This union ensures that when Christ died, we died; and when He arose, we arose with Him (Galatians 2:20). Realizing this truth empowers believers with the comfort that nothing can separate us from Christ's love, reinforcing our security in His grace.