1 Corinthians matters to historians of early Christianity out of proportion to its length because it is dated with unusual confidence, written within about twenty five years of the events it discusses, well before any of the Gospels. Chapter 15's creedal formula, "that Christ died for our sins... was buried... was raised on the third day... and appeared," is widely judged by critical scholars, including many skeptical of the resurrection itself, to predate Paul's own letter by some years, making it the earliest surviving statement of core Christian belief in any form.
The letter's eleventh chapter also preserves the earliest written account of the Lord's Supper's institution, "this is my body, which is for you," older than any of the parallel Gospel accounts, since Paul says he received it "from the Lord" and is passing it on to a church he founded around the year 50. Because it addresses a real congregation's real disputes rather than laying out doctrine in the abstract, 1 Corinthians has become the primary New Testament text cited in debates across many later centuries about church order, spiritual gifts, and the roles of women in worship, chapters 11 and 14 in particular, positions on which sincere readers within the same tradition continue to disagree.