I’m teaching Galatians over the summer and again this fall, and I’ll almost certainly be using Bruce Longenecker’s book, The Triumph of Abraham’s God: The Transformation of Identity in Galatians.
He wonderfully captures Paul’s apocalyptic vision, framing the issues in terms of competing realms and competing sovereignties. The Galatians must decide which realm they will inhabit—the present evil age, dominated by the cosmic powers of Sin and Death, or the realm of God’s new creation in Christ, animated by God’s own Spirit. Their community life of destruction and division or of unity and cruciform love says much about who has a rightful claim to cosmic lordship.
Regarding the present evil age, its dynamics, and what it says about cosmic realities:
What liberation theologians call ‘structures of evil’ corresponds to some extent with what Paul calls the ‘power of Sin’, a controlling force that predetermines the direction, course, and possibilities of the lives of those who are born into the post-Adam ‘world’. For them, only one option exists: to serve the purposes of the power of Sin by their own sin. In a sense, the power of Sin has managed to set up a system, a society, a world, in which things have an almost natural way of running contrary to the will of God. And this, of course, has ramifications concerning whose sovereignty such a ‘world’ advertises; a world order permeated by sinfulness is under the apparent sovereignty of the powers of Sin and Death. So Death, itself conceived of as a cosmic power (cf. 1 Cor. 15; Rom. 8.38), can be said to ‘reign’ (5:14, 17), just as Death’s accomplice also reigns, the power of ‘Sin’ (5:21; cf. 5.12) (pp. 40-41).
Regarding God’s triumph and supremacy in relation to the existence, flourishing, and unity of the church:
Accordingly, in Paul’s thought, God’s ‘oneness’ – that is, God’s sovereignty, supremacy over competing deities, and worthiness as the one who alone is to be worshipped – is advertised in the social constituency of God’s people. God’s eschatological triumph results in, consists, of, and is exhibited by, the establishment of a community of catholic membership. The formation of such a group is itself the placard, the display, and the disclosure of the power of the ultimate divinity (p. 57).