Lord's Day 16

Following the act of justification, wherein God declares us righteous in Christ Jesus, we are then also adopted by the grace of God as His children. J.P. Boyce defines our adoption as “that privilege, bestowed upon those who are united with Christ, and justified by faith, by which they are admitted into the family of God, adopted as his children, and made joint heirs with his own Son.”(Boyce, Abstract of Systematic Theology, www.founders.org/library/boyces-abstract-of-systematic-theology-chapter-36/) 

Through the doctrine of Adoption we are taught that those who are justified are taken, or received, as the very children of God. Much like an adoption today, where by judicial decree a legal relationship between parent and child is permanently established, our relationship as the children of God is effectively established by His decree. God's name is given to us, so that we are now members of the household of faith and of the family of God. In this new relationship, we receive the Holy Spirit, who is also called the spirit of adoption (Rom 8:15), and we are said to now have the spirit of the children of God (Rom 8:16). 

As with any adoption, our adoption by God comes with many privileges and responsibilities. As the adopted children of God, we are privileged to call God, Father. Moreover, having been adopted by God, we have the benefit of being cared for by our heavenly Father, who constantly provides us with every good and perfect. We may even consider God’s discipline as a privilege of being His adopted children, for in His fatherly love and care God corrects and chastises us for our sins, in order that we might grow in grace. Finally, by means of our adoption, we may be even more assured of our ultimate salvation. Scriptures teach that as the children of God we have been sealed by the Holy Spirit for the day of redemption, we are heirs of God through Jesus Christ and heirs of all the promises of God, and fellow-heirs with Christ in glory.