Q 66 What is that union which the elect have with Christ?

A.
The union which the elect have with Christ is the work of God’s grace,[270] whereby they are spiritually and mystically, yet really and inseparably, joined to Christ as their head and husband;[271] which is done in their effectual calling.[272]

[270]
Ephesians 1:22. And hath put all things under his feet, and gave him to be the head over all things to the church.

Ephesians 2:6-7. And hath raised us up together, and made us sit together in heavenly places in Christ Jesus: That in the ages to come he might show the exceeding riches of his grace in his kindness toward us through Christ Jesus.

[271] 1 Corinthians 6:17. But he that is joined unto the Lord is one spirit.

John 10:28. And I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand.

Ephesians 5:23, 30. For the husband is the head of the wife, even as Christ is the head of the church: and he is the saviour of the body.... For we are members of his body, of his flesh, and of his bones.

[272] 1 Peter 5:10. But the God of all grace, who hath called us unto his eternal glory by Christ Jesus, after that ye have suffered a while, make you perfect, stablish, strengthen, settle you.

1 Corinthians 1:9. God is faithful, by whom ye were called unto the fellowship of his Son Jesus Christ our Lord.