They had the books of the Holy Bible, which all existed, but at first they weren’t all together in one volume. The various books of the Bible circulated among the churches in individual scrolls. In the second century the Codex (a modern book style) was invented, and within a couple of centuries they were putting all the books together in a codex.
But how did they know which books? If we grant that the early church was competent in declaring which books were Scripture then it was equally competent in declaring what was Christian doctrine. And if the church in the first centuries was competent to do this then it is so today. Without the declaration of the church we would not know what were the books of the Bible in the first place.
“They had the books of the Holy Bible, which all existed, but at first they weren’t all together in one volume. The various books of the Bible circulated among the churches in individual scrolls. In the second century the Codex (a modern book style) was invented, and within a couple of centuries they were putting all the books together in a codex.”
Yep. Nor did it mean any church was missing some truth necessary for salvation in the meantime: the gospels were widely circulated, and the letters expounded on various errors and revealed other encouraging things to the first century Christians.