A. 1 Now I say, That the heir, as long as he is a child, differeth nothing from a servant, though he be lord of all; 2 But is under tutors and governors until the time appointed of the father. 3 Even so we, when we were children, were in bondage under the elements of the world:
B. 4 But when the fulness of the time was come, God sent forth his Son,
C. made of a woman, made under the law, 5 To redeem them that were under the law, that we might receive the adoption of sons.
B’. 6 And because ye are sons, God hath sent forth the Spirit of his Son into your hearts, crying, Abba, Father.
A’. 7 Wherefore thou art no more a servant, but a son; and if a son, then an heir of God through Christ.
I’ve expanded on this chiasm and have found that it ultimately points to redemption. This follows the theme that Paul is writing on here; that Christ is our redemption rather than the Law. This was the problem the church in Galatia was struggling with.
A. Heir v.1
B. He is a child v.1
C. Servant v.1
D. The father v.2
E. God sent forth his Son v.4
F. Under the law v.4
G. To redeem v.5
F’. Under the law v.5
E’. God has sent forth the spirit of his Son v.6
D’. Abba, Father v.6
C’. Servant v.7
B’. But a Son v.7
A’. Heir v.7
I expanded this one quite a lot, maybe a bit too much. But I believe that having redemption as the center of the structure is intentional.