NOTES for Co1 15:3-5
Paul's words about the Savior's death and resurrection, with the addition "according to the Scriptures," are very curious. What "scriptures" are in view? The corresponding Hebrew word designates the third part of the Jewish canon of Holy Scripture, which took shape much later.
In Paul's time the Holy Scripture of Judaism included the Torah, the Former Prophets, our historical books except Chronicles, and the Latter Prophets, our prophetic books except Daniel, which in the Jewish canon does not belong among the prophetic books.
In New Testament books the Jewish canon of Holy Scripture is usually called "the Law and the Prophets," meaning precisely the Torah, that is, the Pentateuch, and the prophetic books, the Former and Latter Prophets. The third part of the Jewish canon, called by the word "Writings," took shape much later, in the third to fourth centuries AD. This third part included our wisdom books, as well as Chronicles, the Book of Psalms, and the Book of Daniel.
These books appeared much earlier, even before Christ's coming, but in those days the Synagogue regarded them as authoritative books useful for reading, though not included in the canon of Holy Scripture. The composition of the "Writings" therefore was not exactly defined; it varied by region and by local traditions, often including books not only in Hebrew but also in Greek.
It is not impossible that the first generation of Christians also had their own version of "Writings." These were not yet, of course, the Gospels we know, but their core may already have been written down in those days.
Indeed, the foundation of all four Gospels is the account of the Savior's resurrection, which is not surprising: the Resurrection is the brightest and unique testimony to Jesus' messiahship and to the truth of His words about the Kingdom that He brought into the world. The preaching of Paul, like that of all the other apostles, was built on the testimonies to the Resurrection.
Meanwhile, the account of the Resurrection is, in form, a collection of testimonies, and such testimonies need the most exact recording possible. It is no surprise that testimonies of people connected with the Resurrection began to be recorded and systematized very early, already during the lifetime of the first Christian generation.
It is possible that these written accounts were well known to the first Christians, and Paul could refer to them, being sure that his hearers knew what he meant. Thus personal testimony was supplemented by written sources: written sources testified to the reliability of the Resurrection as a real historical event, while personal experience, testified to by such witnesses as Paul himself, for example, proved that the Resurrection is not only history but also the reality of the life of every Christian, regardless of where and when he lives.