If I were asked that question my first answer would be this: justification by faith.
And in the year of the 500th anniversary of the Reformation my answer would come all the more readily. But I’d be wrong.
I can still remember first reading Knowing God by the famous theologian J.I Packer where I discovered my mistake.
There he explains the greatest blessing we have as Christians is this: adoption as sons.
“Adoption is the highest privilege that the gospel offers, even higher than justification. Justification is the primary blessing of the Gospel because it meets our primary spiritual need. We all stand condemned under God’s judgment. So we need forgiveness of sins and assurance of a restored relationship with God before we need anything else in the world.
But this is not to say that justification is the highest blessing of the Gospel. Adoption is higher, because of the closer relationship with God that it involves.
Justification is a forensic idea conceiving God as judge. Adoption is a family idea conceived in terms of love and viewing God as father. In adoption God takes us into his family and fellowship and establishes us as his children and heirs.
To be right with God as judge is a great thing. But to be loved and cared for by God the Father is a greater.” (p187)
Packer immediately goes on to cite Galatians where justification leads to the greater blessing of adoption:
“But when the fullness of time had come, God sent forth his Son, born of woman, born under the law, to redeem those who were under the law, so that we might receive adoption as sons. And because you are sons, God has sent the Spirit of his Son into our hearts, crying, “Abba! Father!” Galatians 4:4-6.
And so next time you are thinking of what the greatest blessing we have as Christians is, remember that we are adopted as children of God and we are able to call him our Father.