The use of the term ‘adoption’ to describe membership of the family of God is a Pauline metaphor, occurring in Paul’s letters to the Romans, Galatians and Ephesians. But in order to have a full biblical appreciation of the doctrine other teachings that approximate to the concept of adoption must be included, teachings such as John’s references to children of God and the teaching of Jesus on the Fatherhood of God which are recorded in the Gospels. In the New Testament two standard terms, in the main, are used to describe this relationship with God: huios (son) and teknon (child), with Jesus and John using teknon and Paul using both terms. Two other areas that must be considered are (1) whether or not humans are God’s children by his act of creation and (2) Old and New Testament statements which indicate that Israel, as a nation, had a relationship of sonship to God. These all need to be taken together in order to gather the full biblical understanding of belonging to the family of God.
I would add that the primary source for the Christian understanding of this doctrine is the Bible. It may be the case that other sources, such as the study of comparative religions, may provide evidence that there has been or still is a concept of sonship among humankind. Arguments also may be deduced from theistic philosophy concerning the likelihood of the supreme being functioning as a father. The basic reason for this emphasis on the exclusivity of the Bible is that the Bible is divine revelation and when correctly interpreted is the final authority on the doctrines it contains.
The necessity of correct interpretation means that attention needs to be paid to the historical understanding of the doctrine. It is claimed that in the past the doctrine of adoption was not given the attention it deserves, either at a scholarly or at a popular level, until the theological controversy in mid-nineteenth century Scotland following the publication of the first series of Cunningham Lectures, delivered on the subject of adoption by R.S. Candlish, a leading Free Church of Scotland preacher, ecclesiastic and theologian. His volume resulted in a major response from Thomas J. Crawford of the Church of Scotland, who strongly opposed the view of Candlish, arguing that humans are God’s sons by creation. There were also two minor responses to both Candlish and Crawford from Dr. John Kennedy of Dingwall in his Man’s Relations With God and from Peter McLachlan, a Free Church of Scotland minister in Glasgow who wrote The Divine Sonship of Man. Hugh Martin, a Free Church of Scotland minister, also wrote a lengthy review of Candlish’s book in The British and Foreign Evangelical Review.
Concerning previous studies on adoption, Kennedy commented: ‘The act of adoption constitutes a new relation to God. The line of this relation has not hitherto been distinctly traced. This was not done even by such theologians as Calvin, Turretine, and Mastricht. The distinction between the result of justification, as affecting the relational status of those who are in Christ, and the peculiar effect of their being adopted as children of God, even those eagles failed to see. Their successors have hitherto added but little to their labours in this department of theology; and notwithstanding a recent discussion, by learned Doctors, of this subject, a clear definition of adoption, and a just description of its effects, on the relation between believers and God, are still awanting.’
The debate between Candlish and Crawford also resulted in American contributions to the doctrine, with John L. Girardeau, professor at Columbia Theological Seminary in South Carolina, writing a short treatise on the doctrine and his son-in-law R. A. Webb, professor of Systematic Theology at the Presbyterian Theological Seminary in Louisville, Kentucky, writing a volume on adoption. Both writers differed from Candlish but did not adopt all of Crawford’s objections. In recent years, there have been popular treatments of adoption by Sinclair Ferguson (at the time, professor of systematic theology at Westminster Theological Seminary, Philadelphia), Mark Johnston (a pastor in London) and Robert Peterson (professor of systematic theology in Covenant Seminary in St Louis, Missouri).
Sinclair Ferguson suggests two reasons for this previous neglect: first, at the Reformation, the focus was on the doctrine of justification and ‘the idea that we are also made sons and daughters of God was often hidden by the bright glow of our justification by faith’; secondly, in the nineteenth century, liberal theology placed such an emphasis on the universal fatherhood of God and the universal brotherhood of man that evangelical Christians tended to keep clear of the doctrine of adoption.
Douglas Kelly, commenting on the fact that the Westminster Confession of Faith is the only historical confession to give a chapter to the doctrine of adoption, says that this means that ‘those in the official Westminster tradition have far less excuse for this omission than others’. He further comments: ‘This neglect, I think, has been detrimental to the teaching and pastoral balance of large segments of the entire tradition.’
Although the Westminster Confession does have this chapter on adoption, the inadequacy of its treatment has been recognised. Hugh Martin, for example, after acknowledging the Confession’s treatment, goes on to say that ‘as to any scientifically theological treatment of the doctrine, such as they [the Confession and Catechisms] have so conclusively and exhaustively bestowed on the question of justification by faith, we entirely agree with Dr Candlish in thinking that there is here a very remarkable contrast. Of the grounds or grounds of this privilege and relation we find in them absolutely nothing, save the vaguest and most general reference….Of God’s procedure in constituting the relation, they leave us in complete ignorance. On the believer’s action in apprehending it, they are equally silent. Of the connection between adoption and regeneration, they tell us nothing. And as to what relation or connection subsists between the Sonship of Christ and the sonship of his people, they do not even raise the question. But assuredly, these are just the aspects of the question which it behoves theology, as a science, to face, discuss, settle and formulate.’
R. A. Webb gives three reasons that indicate the importance of the doctrine: (a) ‘adoption’ is a biblical term which connotes a biblical idea, and that the Spirit of God ‘was not trifling when He inspired its use as one of the verbal symbols through which He would communicate the mind of God to man’; (b) the intrinsic preciousness of the paternal relation of God to his people, and their corresponding filial relation to him, creates a very high claim for adoption; (c) adoption deserves to be magnified because of the distinctive office which it performs in the scheme of saving grace.
For further comments on this important doctrine, see http://www.scalpayfreechurchofscotland.co.uk/RTE/files/fcadoption.asp