Answer: The union which the elect have with Christ is the work of God’s grace₁, whereby they are spiritually and mystically, yet really and inseparably, joined to Christ as their head and husband₂; which is done in their effectual calling.₃

1. Ephesians 1:22; Ephesians 2:6-8
2. 1 Corinthians 6:17; John 10:28; Ephesians 5:23; Ephesians 5:30
3. 1 Peter 5:10; 1 Corinthians 1:9