What is adoption?
Adoption is an act of the free grace of God,1 in and for his only Son Jesus Christ,2 whereby all those that are justified are received into the number of his children,3 have his name put upon them,4 the Spirit of his Son given to them,5 are under his fatherly care and dispensations,6 admitted to all the liberties and privileges of the sons of God, made heirs of all the promises, and fellow heirs with Christ in glory.7
Scripture proofs
The Westminster Assembly's proof texts (KJV). The bracketed numbers in the answer above mark the clause each set of references supports; expand a row to read the verses.
1 1 John 3:1
Behold, what manner of love the Father hath bestowed upon us, that we should be called the sons of God: therefore the world knoweth us not, because it knew him not.
2 Eph. 1:5; Gal. 4:4–5
Having predestinated us unto the adoption of children by Jesus Christ to himself, according to the good pleasure of his will,
Gal. 4:4 But when the fulness of the time was come, God sent forth his Son, made of a woman, made under the law,
Gal. 4:5 To redeem them that were under the law, that we might receive the adoption of sons.
3 John 1:12
But as many as received him, to them gave he power to become the sons of God, even to them that believe on his name:
4 2 Cor. 4:18; Rev. 3:12
While we look not at the things which are seen, but at the things which are not seen: for the things which are seen are temporal; but the things which are not seen are eternal.
Him that overcometh will I make a pillar in the temple of my God, and he shall go no more out: and I will write upon him the name of my God, and the name of the city of my God, which is new Jerusalem, which cometh down out of heaven from my God: and I will write upon him my new name.
5 Gal. 4:6
And because ye are sons, God hath sent forth the Spirit of his Son into your hearts, crying, Abba, Father.
6 Ps. 103:13; Prov. 14:26; Matt. 6:32
Like as a father pitieth his children, so the LORD pitieth them that fear him.
In the fear of the LORD is strong confidence: and his children shall have a place of refuge.
(For after all these things do the Gentiles seek:) for your heavenly Father knoweth that ye have need of all these things.
7 Heb. 6:12; Rom. 8:17
That ye be not slothful, but followers of them who through faith and patience inherit the promises.
And if children, then heirs; heirs of God, and joint-heirs with Christ; if so be that we suffer with him, that we may be also glorified together.
This doctrine across the Standards
Where the Confession and the Westminster Shorter Catechism treat the same matter, so the question can be studied alongside its parallel statements.
In the Westminster Confession
XII.1 All those that are justified God vouchsafeth, in and for his only Son Jesus Christ, to make partakers …
All those that are justified God vouchsafeth, in and for his only Son Jesus Christ, to make partakers of the grace of adoption; by which they are taken into the number, and enjoy the liberties and privileges of the children of God; have his name put upon them; receive the Spirit of adoption; have access to the throne of grace with boldness; are enabled to cry, Abba, Father; are pitied, protected, provided for, and chastened by him as by a father; yet never cast off, but sealed to the day of redemption, and inherit the promises, as heirs of everlasting salvation.
→ XII.1 · Of AdoptionIn the Westminster Shorter Catechism
Q.34 What is adoption?
Adoption is an act of God's free grace, whereby we are received into the number, and have a right to all the privileges, of the sons of God.
→ Open Q.34