The subject of adoption is still running. It was not just mentioned in one word and never referred to again.
What has been revealed was a mystery locked in the heart of God. What is more inaccessible to us than the heart of God? There is no possible way that we can force God to tell us his will, no bribe that we could offer him, no threat that we could make, and we have no right to expect him to divulge anything to such sinners as we are. Heaven is beyond our reach and what God does not choose to reveal to us stays forever hidden from us. There is nothing that man can do to uncover what God has covered. Yet there is no place that contains such important and far-reaching secrets as the heart of God. He is the God who cannot be thwarted in anything that he plans to do. For him nothing is uncertain or contingent, for his will determines reality.
Can we be trusted to handle anything he tell us wisely? You share your deepest secrets with those you trust not to take advantage of you. Who do you let in on your plans? Those who are on your side, of one mind with you. God has shared the most glorious aspects of his eternal plan with all the church so that they have become his confidants. These things remain a mystery to those who do not believe though they may read from the Scriptures the same truths as believers read, their minds remain blinded to the wonder of these things because the Spirit of God does not personally unlock these mysteries to them. To the apostles first and then through them to all the church the mystery of God’s will has been made known.
Why should God reveal his will to us? He has done so in recognition of the amazing intimacy between Christ and his church. Abraham was called the friend of God and was made privy to the details of what God intended to do to Sodom and Gomorrah. But what God shared with Abraham, he has also shared with the church so that Christ calls all his disciples friends (John 15:15). Living in New Testament times, we have been shown in great detail what Abraham saw in shadowy form. Who are we that such secrets should be shared with us? But since God has done so, we should not fail to esteem these things very highly. We do not proceed through life as those who do not know God, but we are spectators of his amazing workmanship. God’s plans rise high above the plans of men; this plan involves every single human being that has ever lived and their eternal destiny.
John Dagg, the 19th century American thinker, preacher, theologian was severely disabled and blind, but he was a great thinker and he wrote the first Baptist systematic theology. He had many wonderful epithets, and here is a very simple one which is relevant here: ‘A judge can acquit us, but only a father can adopt us.’ The fatherliness of God is the doctrine of adoption. The brotherliness of Jesus Christ the Lord, the Son of God, is in adoption. And the indwelling, of course, of the Holy Spirit.