From Slavery to Sonship
Paul develops the heir illustration: a child-heir may possess the promise but, while immature, lives under guardians. Then comes the turning point—“when the fulness of the time was come,” God sent his Son, born of a woman and under law, to redeem those under law so that they might receive adoption. God also sends the Spirit of his Son into believers’ hearts crying “Abba, Father.” The movement is from slavery to sonship, from minority to inheritance, and it is accomplished by the sending of both Son and Spirit.