“First, Paul’s strategic deployment of scriptural texts is profoundly contextual, taking into account both the near context and the larger narrative context from which he quotes.
Second, Paul’s exegesis is salvation-historical in orientation, meaning that the location of his OT allusions and citations within the entire arc of the biblical story of God’s redemption of his people is significant.
Third, Paul employs a typological methodology to correlate different texts, figures and events of salvation history in a theologically meaningful pattern. Thus Paul often cites in tandem thematically related texts from patriarchal and Israelite narratives (see Gal 3:6-9, 10-14; 4:21-31), inviting his readers to find significant elements of historical continuity in God’s dealings with his people. For example, by viewing the typological correlation of the Abrahamic and Israelite images in Galatians 4:21-31, it becomes clear that Paul (unlike many modern covenant theologians) does not explain the Old and New Covenants exclusively in temporal terms (i.e., before/after Christ). Instead, by linking the New Covenant with Abraham, and the Old Covenant with Moses, Paul shows how the new surpasses the old precisely because it preceded it, in view of the promise and oath that God pledged to Abraham.
Fourth, Paul argues in a teleological style. In other words, he deploys OT citations and allusions earlier in his discourse with a view to a certain endpoint or telos, that is, a scriptural argument or conclusion introduced only later or at the end of his discourse. For example, the typological interpretation of Genesis 16-21 in Galatians 4:21-31 forms a certain climax of Paul’s argument in Galatians, shedding light on the scriptural citations employed earlier. Thus, interpreters need to read Paul’s arguments in both directions, since later portions shed light on earlier ones, and vice versa.”