They're talking about the Jewish scriptures, i.e. the Old Testament. While some of Paul's letters may have been in circulation in some areas, the only compilation of scripture available was what we call the OT. The bible, as we know it today, did not exist for hundreds of years later.
Also in Acts; the early church days when the practice started in sharing epistles.
Acts 15:3 And they wrote letters by them after this manner; The apostles and elders and brethren send greeting unto the brethren which are of the Gentiles in Antioch and Syria and Cilicia. 24 Forasmuch as we have heard, that certain which went out from us have troubled you with words, subverting your souls, saying, Ye must be circumcised, and keep the law: to whom we gave no such commandment: 25 It seemed good unto us, being assembled with one accord, to send chosen men unto you with our beloved Barnabas and Paul, 26 Men that have hazarded their lives for the name of our Lord Jesus Christ. 27 We have sent therefore Judas and Silas, who shall also tell you the same things by mouth. 28 For it seemed good to the Holy Ghost, and to us, to lay upon you no greater burden than these necessary things; 29 That ye abstain from meats offered to idols, and from blood, and from things strangled, and from fornication: from which if ye keep yourselves, ye shall do well. Fare ye well.
30 So when they were dismissed,
they came to Antioch: and when they had gathered the multitude together,
they delivered the epistle:
Antioch appears to be the center for dispensing the epistles to the churches abroad.
Acts 11:26 And when he had found him, he brought him unto Antioch. And it came to pass, that a whole year they assembled themselves with the church, and taught much people. And the disciples were called Christians first in Antioch.
Anyway, reads to me that the four gospels and the epistles were spreading about to all the churches even back then. Why else were they having argument of genealogies which I attribute that can stem from the gospels of Matthew & Luke?
Titus 3:8 This is a faithful saying, and these things I will that thou affirm constantly, that they which have believed in God might be careful to maintain good works. These things are good and profitable unto men. 9 But avoid foolish questions, and
genealogies, and contentions, and strivings about the law; for they are unprofitable and vain. 10 A man that is an heretick after the first and second admonition reject;
