Westminster Larger Catechism
Q. 74. What is adoption?
A. Adoption is an act of the free grace of God,[307] in and for his only Son Jesus Christ,[308] whereby all those that are justified are received into the number of his children,[309] have his name put upon them,[310] the Spirit of his Son given to them,[311] are under his fatherly care and dispensations,[312] 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.[313]
Westminster Shorter Catechism
Q. 34. What is adoption?
A. Adoption is an act of God’s free grace,a whereby we are received into the number, and have a right to all the privileges, of the sons of God.[96]