The Scriptures being the Hebrew Scriptures for collaboration of Paul’s testimony that Jesus is the Messiah.
You don’t read scripture much? Even your beloved Peter said what Paul wrote was included in scripture.
2 Peter 3:15b. As also our beloved brother Paul wrote to you, according to the wisdom given him, [16] as in all his letters, speaking concerning these matters, in which some things are hard to understand, which those who are untaught and unstable twist to their own destruction, as they do also THE OTHER SCRIPTURES. [17] You then, beloved ones, being forewarned, watch lest you also fall from your own steadfastness, being let away with the delusion of the lawless.