After Paul's Gospel

Sources: I. Howard Marshall et al., Exploring the New Testament: A Guide to the Letters and Revelation (IVP, 2002); Raymond E. Brown, The New Testament: an Introduction (Doubleday, 1997); Bart Ehrman, The New Testament: A Historical Introduction to the Early Christian Writings, 3d ed. (Oxford, 2004).

The Marks of Jesus: The Gospel in Galatians
Paul's churches in Galatia face teachers of unknown origin (5:10):

Christian teachers (from Jerusalem?) are commanding Torah obedience, signified by circumcision (1:6-9, 2:6-2:21, 6:12-13; cf. Gen. 17:9-14).
For the Gentile, formerly pagan Galatians (4:8), this would amount to telling 'a different gospel' (1:6) than the good news of the grace of the Messiah (1:1).

Paul must overturn their claim that Torah observance is mandated by God to the faithful:

While his opponents' teachings are human (1:6-10), Paul's gospel is divine in origin (1:1, 1:11-2:10, 3:3).
The Jerusalem church already agreed with him in a similar controversy (2:4-10, 2:11-14).
Justification is not through the law but Jesus the crucified (2:15-3:1, 3:10-14, 6:14-17).

The Torah is on Paul's side, not theirs (3:6-5:15):

Abraham's righteousness is from faith in God's promise rather than covenant circumcision (3:6-18).
Abraham's legacy goes in two ways; only one leads to freedom (3:15-18, 4:21-31).
Servitude has its place as preparation, but heirs are free (3:19-4:11, 5:13-26).
So circumcision severs (!) from Christ rather than associating with him (5:1-12).

But demanding circumcision is a presenting symptom of a deeper spiritual issue: refusing Christ's gift in 'the present evil age' (1:4).

His opponents' theology's origin, shape, and effect are human (1:11-12), insincere (2:12-14), retrograde (2:18-21, 3:3, 4:9, 5:1-4), confining/enslaving (3:22-24, 4:8-11 4:25, 5:1), selfish/'fleshly'/vainglorious (3:3, 4:17-20, 5:13-26, 6:8-17), un-faith-ful (5:2-8), fleshly (5:13-24, 6:8, 6:12-13).
Paul's motive and outcome is faithfulness in conformity with Christ in his cruciform sufferings (2:20-3:1, 5:11, 5:24, 6:12, 6:17) and in the power of his Spirit (4:12-16, 6:1-10, 6:14-16).

Paul thus crafts a brilliant, dense rabbinical argument to turn the tables on his opponents, diagnose the heart of their issue, and restore the integrity of the Galatians' trust in Christ.
Galatians focuses more on what to avoid ...

Bring It to Completion: The Gospel in Philippians
... and Philippians focuses more on what to embrace.
1:27-30 introduces the instructions that follow as a "life worthy of the gospel":

Christlike humility embodies Christ's divine character and salvation (2:1-13).
Discuss: How does Paul draw on Isaiah 52:13-53:12 and Isaiah 45:18-25 in this hymn?
Fellowship strengthens sufferers (2:14-30).
Faith takes on the cross and awaits resurrection rather than trusting in "the flesh" (3:1-4:1).
Pursuing peace is sharing the work of the gospel (4:2-20).

All this faithfulness yields no more or less than hope of salvation (1:28).
Discuss: Where do you see those three focal lenses (cross/community/new creation)?

Excursus: The Terminology of a Text
Certain words (Herzwort) play key roles in a language, a culture, a corpus, and a text.

Some key American terms: liberty, justice, right.
The meanings of these (and all) terms are specific to their community.
Key terms may still be infrequently used.
Other terms are much less important and even dispensable.

Word studies discover and explore the meanings and roles of key terms of a discourse (e.g., grace, gospel, justify, faith, flesh, peace, joy). Some pointers:

Word studies should pay close attention to contexts.
They should not import every meaning of a word into every use!
They should look for resemblances across authors.
They should not ignore differences between authors!
They should be aware of lines of influence (see "genre").
They should not ignore the evolution of usages over time!
They should choose terms that reflect the text's emphasis.
They should not treat the meaning as inhering in the word itself.

How Pauline Are We?
These letters reject legalism, moralism, and libertinism in favor of cooperation ("incarnating the gospel").
Are our churches really familiar with the messages of these books?
Have our theologies turned Paul into someone else?