These background notes are for 1 Corinthians 15: 20-34.
Verse 20: “First fruits” represented the beginning of the harvest (Exodus 23:19; Leviticus 23:10; Jeremiah 2:3), a first installment (cf. Romans 8:23).
21-22: In 15:21-22, Paul introduces the concept between Adam and Christ that he will take up again in 15:45-49; Jewish people often affirmed that the end-time would parallel what God had done at the beginning (envisioning paradise as a new Eden).
23-25: Paul envisions the sequence of events based on Psalm 110:1 (as becomes explicit in 15:25): Christ must reign at God’s right hand until his enemies are subdued (for his reign, cf. also Isaiah 9:6-7; Daniel 7:14).
26: All enemies must be subdued (Psalm 110:1); no other enemy can possibly outlast death itself, so the resurrection coincides with Christ’s final victory.
27: Paul shows that the only exemption from what is subdued under him is God himself, as is clear from the verse (Psalm 8:5) immediately preceding his citation (Psalm 8:6). If the ruling “human one” in Psalm 8:4 alludes to humanity’s commission to rule in Genesis 1:26-28, Paul is preparing for his contrast with Adam in 1 Corinthians 15:45-49.
28: “All in all” was a rhetorical way to emphasize everything significant. (Although Stoic philosophers used such expressions pantheistically, Jews who used the language did not mean it this way.)
29: There is no consensus what this baptism means. Perhaps Paul alludes to the analogy of 2 Maccabees 12:43-45, where prayer for the dead is unreasonable unless the dead are raised. Perhaps he refers to baptism before they died in hope of the future resurrection; or baptism on behalf of a converted friend who failed to be baptized first. There is no evidence for vicarious baptism for others who are dead in this period, but perhaps it was a local Corinthian idea.
30-31: Danger every hour and dying every day are probably both hyperbole (for very real danger and suffering; cf. Psalm 44:22; 119:109).
32: Corinthians would readily understand the image, since Corinth had recently (A.D. 54) instituted annual imperial festivals that included wild beast “shows.” Ephesus also had gladiatorial shows. Nevertheless, the sentence of battling wild beasts in the arena was a death sentence, so those who did it did not normally live to tell about it. Paul thus undoubtedly applies the image figuratively. Philosophers spoke of the irrational as beasts, and Scripture compared human enemies with hostile beasts (e.g., Psalm 22:16; 74:19).
Paul cites the words of the wicked in Isaiah 22:13, who will face judgment (Isaiah 22:14). Similar depictions applied to those who denied an afterlife, such as Epicureans (cf. also Wisdom of Solomon 2:1-20)
33: Sages emphasized companionship with the morally edifying (e.g., Proverbs 13:20), and Paul here cites a Greek proverb (first known to us in Menander’s comedy “Thais”).
34: The educated and philosophically astute prided themselves on their knowledge (cf. 8:1), especially about eternal matters.
(Adapted from Dr. Keener’s personal research. Used with permission from InterVarsity Press, which published similar research by Dr. Keener in The IVP Bible Background Commentary: New Testament. Buy the book here.)