Why is the concept of eternal union with Christ significant?

The concept of being eternally united with Christ is significant because it speaks to the nature of salvation through grace alone. In the sermon, it's emphasized that our union with Christ is established by God’s sovereign choice, who, out of love, ordained a way for His elect to be saved through Christ's righteousness. This union is foundational because it assures believers of their salvation and identity in Christ, as they are seen as His workmanship created for good works. It means that believers are not just connected superficially but are given a new nature that desires to obey God and produce spiritual fruit.