“What is a “scripture” ?”
In that verse, it means the Torah and Tanakh of the Hebrews. The word used translated literally as “writings”, with the implied sense of “holy writings”, and those were the only holy writings that would have been recognized by the people being spoken to.
What made them “holy’? Was it The Council of Laodicia in 311 A.D.? What about the estimated 3000 writings rejected ? Just asking.